The Regional Court of Cologne has ordered Telekom Deutschland to stop replacing the network name on its customers' smartphones with the advertising slogan "Im besten Netz" ("On the best network"), finding that the campaign amounted to an unreasonable nuisance to consumers under German unfair competition law. The judgment, case 33 O 55/26, is dated September 17, 2026, and was published on October 26, 2026, by the Federation of German Consumer Organisations (vzbv), which brought the case. It is not final. According to vzbv, Telekom has appealed to the Higher Regional Court of Cologne, where the case is registered as 6 U 103/26.

The dispute concerns a handful of characters in the corner of a screen. For a few weeks at the start of 2026, Telekom customers who looked at their lock screens saw the company's marketing claim where the name of their mobile network normally sits. The 33rd Civil Chamber of the court decided that this small swap crossed a line. "The display of the network identifier was repurposed as an advertising banner," the judgment states.

In Short

A German court has banned Telekom from showing its "best network" slogan in the spot on customers' phones where the name of the mobile network normally appears. The ruling treats a phone's lock screen as part of a person's private sphere, which matters to any carrier, device maker or app company that controls a screen and wants to put promotions on it. Telekom has appealed, but for now the court's position is that this kind of ad needs customers' consent or an opt-in, and that being a paying customer does not amount to agreeing to it.

What the court ordered

The operative part of the judgment has four points. The first is an injunction. Telekom must refrain, "in the course of business dealings with consumers, from altering the network identifier on smartphones in such a way that, instead of displaying the network used by the consumers, the advertisement 'On the best network.' is displayed." Each violation carries a fine of up to €250,000 or, alternatively, detention of up to six months, to be enforced against the company's legal representatives.

The second point is money, though not much of it. Telekom must pay vzbv €350, the flat-rate cost of the association's warning letter, plus interest at five percentage points above the base rate from February 28, 2026. Third, Telekom bears the costs of the litigation. Fourth, the judgment is provisionally enforceable: the injunction against security of €15,000, and the rest against 110% of the amount to be enforced. The court set the amount in dispute at €15,000.

The order is tied to a specific design. The injunction covers the slogan as it appeared in vzbv's evidence, and the court described its ruling as granting "an injunction against the specific advertising design referred to." It does not, on its face, regulate every change a network operator might make to the name its network broadcasts.

The chamber held its oral hearing on July 16, 2026. A court clerk's certification on the judgment is dated September 18, 2026. Cologne had jurisdiction under Section 14 of the Unfair Competition Act (UWG) and a North Rhine-Westphalia regulation on court jurisdiction in civil matters; Telekom's general place of jurisdiction is Bonn, where the company is based.

How a network name became an advertisement

The judgment sets out the mechanism in two sentences, and the technical detail is part of what makes the case unusual. According to the court, Telekom changed "the administrative information of its network" so that the network identifier switched from "Telekom.de" to the slogan. That changed name was then transmitted to devices through NITZ, short for Network Identity and Time Zone, "when the respective end devices dialed in or through a network-triggered update."

No app was involved, no operating system update and no action by the customer. The phone simply displayed what the network told it to display. The slogan appeared on the lock screen and in the Control Center, and the court noted that "the advertisement was not displayed to all of the defendant's customers." Exhibit K1, which the court reproduced in its judgment, shows a lock screen dated Tuesday, January 27, with the words "besten Netz." cut off at the edge of the status bar, and a Control Center view reading "Im besten Netz." beside the signal bars.

Outside reporting fills in the dates. According to GIGA, the new name began reaching millions of smartphones on January 22, 2026, through an over-the-air update. Telekom described the change as a special extra of its campaign and said it would last for an initial four weeks, with no option to switch it off, GIGA reported. Older phones and certain tariffs kept the usual operator name. GIGA later reported that Telekom ended the campaign as planned in mid-February. The campaign itself ran under the name "Besser im besten Netz," according to the law firm GvW Graf von Westphalen.

vzbv moved quickly. In a letter dated January 28, 2026, the association sent Telekom a cease-and-desist notice and demanded a declaration of discontinuance backed by a contractual penalty. Telekom did not sign one.

Telekom's defence

Telekom asked the court to dismiss the complaint, and its arguments are worth setting out because they are the arguments any company in a similar position would likely make.

The first was about location. Harassment, Telekom argued, depends on whether a notice at a particular place is disruptive regardless of its content. Since a network identifier has always appeared in that spot, the company said, there could be no harassment. The second was about duration. "Glancing at the lock screen is merely a brief transitional moment before moving on to the actual use of the phone," the judgment summarises, and customers needed to do nothing more than use their phones for the slogan to disappear.

The third was about the audience. Those who saw the slogan were Telekom's own customers, whom the company described as more open to such measures. The fourth was about precedent: Telekom compared the campaign to pop-up windows, direct mail and door-to-door advertising, all practices courts have permitted. And the fifth was that "Telekom.de" itself already worked as advertising, because it referred people to the company's website, so the public would see the spot as promotional anyway.

The court rejected each of them.

Why the court found harassment

The chamber started by establishing that the slogan was a commercial act at all. Telekom's campaign targeted people who already had contracts with it, but Section 2(1)(2) UWG covers conduct after a contract has been concluded. With the slogan, the court wrote, Telekom sought "to highlight its inherent leading position to its customers in order to possibly persuade them to renew their contracts or amend existing contracts to different terms."

It then applied the test for harassment laid down by the Federal Court of Justice (BGH) in its 2019 WifiSpot decision. A commercial act is harassing if it is imposed on the recipient against their recognisable or presumed will and is perceived as disruptive by its nature, regardless of content. The court found no consent, and no reason to think consumers would welcome more advertising on their private devices. On Telekom's claim that its customers were a receptive audience, the chamber was blunt: "The defendant's view that this target audience is 'open-minded' toward such measures cannot be accepted. Consumers who pay for a service, in particular, will not wish to be confronted with further advertising despite having already paid."

The judgment then turned to the phone itself. "For many consumers, their own smartphone has now become a daily companion and a tool for all forms of private communication and interaction," the court wrote. "The smartphone functions not only as a phone and a small computer substitute, but also, by now, as a digital wallet." Consumers, it concluded, do not expect advertising in "this extended sphere of their privacy without their consent."

Telekom's location argument fared no better. The content of an advertisement is not decisive for harassment, the court accepted, but it matters whether users see a familiar reference to their network or something else entirely in the same place. "At first glance, the majority of affected consumers will feel disturbed and assume that something is wrong with their own network connection," the chamber wrote. "Only upon closer inspection will they realize that it is a (familiar) advertising slogan of the defendant."

As for "Telekom.de," the court found that the average consumer reads the name as a designation for the network, not as an advertisement for a website. Even if it carried some promotional flavour, the change itself was the problem: "By altering what consumers are accustomed to, their attention is drawn to the network identifier more than usual. As a result, the consumer is compelled to take notice of the advertisement and engage with its content."

Why the nuisance was unreasonable

Harassment alone is not enough under Section 7(1) UWG. The nuisance must also be unreasonable, which requires a balancing of the consumer's interest, protected by Article 2(1) of the German Basic Law, in being left alone against the company's interest in promoting its services. The court relied on a leading commentary on the UWG for the proposition that strict standards should not be applied when protecting market participants from harassment.

Several factors pushed the balance against Telekom. The first was intent. Under BGH case law, an advertising method in which disruption is "consciously and deliberately employed in the advertiser's own interest" must generally be classified as unreasonable. The court found exactly that here. "With the advertising campaign at issue, the defendant has created a new advertising method for itself that, at least to this extent, did not previously exist," the judgment states. "The disruptive effect of the advertising campaign is thus deliberately exploited and does not constitute an occasional side effect."

The second was the existence of gentler alternatives. Telekom "had the option of first obtaining its customers' consent as a less intrusive measure or offering the modified network identifier as a voluntary option," the chamber wrote, citing a decision of the Regional Court of Düsseldorf.

The third was that the slogan could not be avoided. Here the court dismantled Telekom's argument about brief glances. A lock screen, it noted, displays push notification previews, the time and customisable widgets, and many users take in what they need from it without unlocking the phone at all. The slogan also remained visible in the Control Center after unlocking, which people open repeatedly during normal use, and it came back each time the phone was locked again. "It is therefore not possible to completely opt out," the court concluded. "In particular, the average consumer cannot disable the display of advertisements in the settings of the respective smartphone."

The fourth was scale, and the risk of copycats. The court refused to compare the slogan to a banner ad that can be clicked away or to a piece of direct mail. Citing a 2020 BGH decision on advertising placed in email inboxes, it warned that "given the defendant's and third-party imitators' ability to reach a significant number of people simultaneously by simply changing the network identifier, there is a concrete risk that these nuisances will accumulate." Earlier BGH case law, which the chamber also cited, points to the danger that competitors who would not otherwise use a method may feel compelled to imitate it.

Finally, vzbv had shown that a large number of Telekom customers found the display disruptive and a significant nuisance. The court gave that evidence "indicative weight" in the overall balancing.

One question the court did not examine is whether Telekom's network is, in fact, the best. The case was about where the claim appeared, not whether it was true.

A second case in Düsseldorf

The Cologne judgment refers, briefly, to a parallel proceeding. Telekom argued that the risk of repetition had disappeared. The court disagreed: Telekom had not signed a cease-and-desist declaration, and the injunction "obtained before the Düsseldorf Regional Court by another petitioner" did not remove the risk either, because Telekom had not yet submitted a declaration accepting that order as final.

The judgment does not name the other petitioner. According to GvW Graf von Westphalen, the law firm that represented it, it was the rival operator 1&1. The Regional Court of Düsseldorf granted 1&1 a preliminary injunction on February 8, 2026, under case number 38 O 32/26, prohibiting Telekom from changing the technical network identifier on customers' phones for advertising purposes. GvW said the campaign had reached millions of users, and that Telekom restored the normal identifier shortly after the injunction.

The Düsseldorf track went further than Cologne in one respect. According to a GvW press release dated October 2, 2026, the Regional Court of Düsseldorf confirmed its injunction by judgment in March 2026 after Telekom objected, and the 20th Civil Senate of the Higher Regional Court of Düsseldorf then dismissed Telekom's appeal in full, under case number I-20 U 63/26. Besides finding an unreasonable nuisance, the Düsseldorf appeal court held, according to GvW, that Telekom processed personal data such as the IMSI, the number that identifies a mobile subscriber, without a legal basis under Article 6 of the GDPR, and that this was actionable by a competitor under Section 3a UWG as a breach of a market conduct rule. GvW said the Düsseldorf judgment cannot be appealed further on points of law.

The Cologne chamber did not address data protection. Its judgment rests on Section 7(1) UWG alone. That leaves two different legal routes, one brought by a competitor and one by a consumer body, arriving at the same result.

vzbv's standing to sue comes from its status as a qualified entity listed under Section 4 of the Injunctions Act (UKlaG). The association is the umbrella body of all 16 consumer advice centres in Germany's federal states.

The responses

Telekom misused the network identifier as an advertising platform and harassed many consumers in doing so, according to Jana Brockfeld of vzbv, who also pointed out that the display could not even be switched off.

Telekom disagrees with the ruling. According to beck-aktuell, the company said it has by far the best 5G network in Germany, citing independent mobile network tests each year, that the "best network" claim is therefore clearly and credibly associated with Telekom, and that it had informed its customers about this competitive advantage. It said it does not share the court's view.

Same chamber, same day

The Telekom ruling was not the only vzbv case the 33rd Civil Chamber decided on September 17. On the same date, after a hearing on the same day in July, the chamber upheld in full a vzbv suit against Snap. Snap now faces fines of up to €250,000 per breach if it uses My AI chat data for advertising without a legal basis, relies on pre-ticked consent boxes, or switches on alcohol and gambling ad topics for minors by default. That case ran under number 33 O 120/24.

The two judgments address different products, but both turn on the same question: what a company may do with a consumer's private space, whether a chat history or a lock screen, in order to sell advertising or promote itself.

Why this matters for advertising

Telekom's slogan was not a paid placement sold to a third-party advertiser. It was a company promoting itself on a surface it happened to control. That makes it a close relative of a wider category of inventory that has grown up on devices, where the company that owns the software layer, rather than the person who owns the hardware, decides what appears on screen.

Home screen advertising on smart TVs is the most developed version. Smart TV makers sell launcher placements that appear at power-on, before any app opens, and LG Ad Solutions was already marketing Screensaver Ads on LG Smart TVs in September 2024. In September 2025, Samsung confirmed ads on smart fridges costing over $1,800, delivered by software update, where single ads could be dismissed but there was no full opt-out. And in October 2026, CleanYourTV gained 30,900 GitHub stars for a tool that disables manufacturer ad packages on Android TV sets, a sign of how some owners respond when they cannot turn such ads off.

Device makers, or OEMs, and network operators occupy a position that app developers do not: they can change what appears on a screen without asking the user to install or open anything. Does the Cologne reasoning reach that far? The judgment does not rule on TVs, fridges or any surface other than a smartphone status bar, and whether its reasoning would extend to them is untested. But the factors it weighed - no consent, no way to disable, deliberate disruption, and the ease with which one change reaches a large audience at once - are the same features that have drawn complaints about those formats.

There is a parallel in email, and it also involves a telecom operator. In December 2024, the French data protection authority fined Orange €50 million for placing ads among users' emails without consent, relying on a 2021 ruling by the EU Court of Justice on inbox advertising. The Cologne court cited the BGH's 2020 decision in that same inbox advertising litigation. In both cases, an operator placed promotional content in a space that users read as part of the service itself.

The case also lands as telecom operators push further into advertising and into the network layer. Deutsche Telekom and Vodafone tested TrustPID, a network-based alternative to cookies, in 2022, and the European Commission approved the joint venture of Deutsche Telekom, Orange, Telefonica and Vodafone in February 2023. That venture, Utiq, generates pseudonymous IDs from network signals only after explicit consent, and in June 2026 The Trade Desk integrated Utiq's telco identity signals across EMEA. In March 2026, Telekom showed a network-based AI assistant that works inside phone calls without an app. Features delivered from the network reach every compatible device at once. The Düsseldorf and Cologne rulings show where German courts have so far drawn the line when that reach is used for promotion, and the Düsseldorf appeal court's finding on IMSI processing adds a data protection dimension.

The route by which 1&1 succeeded also has a recent precedent. In November 2025, a Madrid court ordered Meta to pay €479 million to Spanish publishers under Spain's unfair competition law, on the basis that Meta's data processing for advertising breached the GDPR and gave it an unfair edge. Read together, the Madrid and Düsseldorf cases show competitors turning data protection breaches into unfair competition claims in disputes over advertising.

Consumer associations do not always win against telecom operators in German courts. In October 2025, the BGH permitted telecoms to share customer data with SCHUFA for fraud prevention, upholding the dismissal of a consumer association's injunction on the basis of legitimate interest. The difference in the network name case is that Telekom's own argument, that its customers were receptive to its promotions, was the one the Cologne court rejected most firmly.

For retention marketing, that point carries weight. Telekom's streaming bundles have been compared with the loyalty tactics that cost Surescripts, and in this case the court read the slogan as an attempt to encourage renewals and contract changes. The judgment holds that an existing contract does not imply consent to promotional messages on the customer's device, and that paying customers may be less, not more, tolerant of them. Whether the Higher Regional Court of Cologne agrees will be decided in case 6 U 103/26.

Timeline

Summary

Who: The Federation of German Consumer Organisations (vzbv), which sued as a qualified entity, and Telekom Deutschland GmbH, the mobile network operator based in Bonn. The 33rd Civil Chamber of the Regional Court of Cologne decided the case. The rival operator 1&1 pursued a separate case in Düsseldorf.

What: The court ordered Telekom to stop replacing the network name "Telekom.de" on customers' smartphones with the slogan "Im besten Netz," which had appeared on lock screens and in the Control Center after Telekom changed its network's administrative information and pushed it to devices via NITZ. The court found the campaign was an unreasonable nuisance under Section 7(1) UWG, backed the injunction with fines of up to €250,000 per breach, and awarded vzbv €350 in warning letter costs.

When: The campaign began on January 22, 2026, according to GIGA. vzbv sent its warning letter on January 28, 2026, the court heard the case on July 16, 2026, and the judgment is dated September 17, 2026. vzbv published it on October 26, 2026. Telekom's appeal is pending as 6 U 103/26.

Where: Germany. The case was heard in Cologne; the parallel 1&1 proceedings ran before the Regional Court and Higher Regional Court of Düsseldorf.

Why: The court held that a smartphone is part of a consumer's private sphere, that paying customers did not consent to further advertising on their devices, that the slogan could not be switched off, and that Telekom deliberately used the disruption of a familiar display to draw attention. It also warned that the method, if permitted, could be copied by others to reach large numbers of people at once. For advertisers and the companies that control device screens, the ruling sets out a consent-based limit on turning system interface elements into promotional space, subject to the outcome of the appeal.