A trilogue is an informal, closed-door negotiation between representatives of the European Parliament, the Council of the European Union and the European Commission, held to agree the final wording of a European Union law. Parliament and the Council, the two co-legislators, must adopt an identical text before any regulation or directive can take effect. Formal readings are slow, so negotiators meet instead and carry a provisional agreement back to their institutions for approval. The word appears nowhere in the EU Treaties. Yet almost every piece of EU digital legislation that governs advertising, from the General Data Protection Regulation (GDPR) to the Artificial Intelligence Act, took its final shape in one.

Where trilogues sit in the legislative process

The formal framework is the ordinary legislative procedure, set out in Article 294 of the Treaty on the Functioning of the European Union (TFEU). The Commission holds the right to propose legislation; Parliament and the Council then decide on it with equal weight. Up to three readings are possible. First reading has no deadline. At second reading each institution gets three months, extendable by one, and a third stage, conciliation, opens only if the Council cannot accept Parliament's second-reading amendments, according to the European Parliament's procedural guide.

Trilogues can happen at any stage, but most now take place during first reading. The Commission publishes a proposal. A lead committee in Parliament appoints a rapporteur, the member of the European Parliament (MEP) who steers the file, and each political group names a shadow rapporteur. The committee votes a report and a decision to open negotiations, which is announced in plenary and can be challenged there. On the Council side, national officials work through the text in a working party, and the Committee of Permanent Representatives (Coreper), made up of member state ambassadors to the EU, approves a negotiating mandate. When ministers endorse it, the mandate is often called a general approach. The rotating Council presidency, held by one member state for six months, then negotiates on behalf of all 27 governments.

Political trilogues begin once both mandates exist. Parliament's team is led by the rapporteur and the committee chair, with shadows attending. The presidency usually sends its permanent or deputy permanent representative, sometimes a minister for the final round. The Commission sits as the third party, defending its proposal and often drafting compromise wording. Between political meetings, advisers and officials hold technical trilogues that work through the text article by article.

The working tool is the four-column document. Column one holds the Commission proposal, column two Parliament's position, column three the Council's, and column four the emerging compromise, as the EU General Court described it in 2018. The European Parliamentary Research Service counted 373 trilogue meetings between July 2019 and December 2021, 129 of them in 2021 alone.

A deal is not yet law. Coreper and the Parliament committee each endorse it, lawyer-linguists revise it into all 24 official languages, Parliament votes in plenary and the Council adopts it formally. Publication in the Official Journal follows, with entry into force set by the act itself.

Origin and evolution

The Maastricht Treaty, in force from November 1, 1993, created the codecision procedure and gave Parliament the power to block legislation for the first time. Informal three-way contacts started in the early 1990s and were progressively formalised, according to the European Parliamentary Research Service. The Treaty of Amsterdam, in force from May 1, 1999, allowed laws to be adopted at first reading, which pulled negotiations forward. Only 17% of legislation was adopted at first reading in 1999-2000. By 2008-2009 the figure was around 80%.

On June 13, 2007, the three institutions signed a Joint Declaration on practical arrangements for the codecision procedure. It endorsed informal trilogues as a route to first-reading agreement and set out how the chair of Coreper would confirm a deal to Parliament by letter. The Treaty of Lisbon, in force from December 1, 2009, renamed codecision the ordinary legislative procedure and extended it to most policy areas.

The European Ombudsman, Emily O'Reilly, opened strategic inquiry OI/8/2015 and on July 12, 2016 asked the institutions to publish trilogue dates, summary agendas, initial positions, participants' names and lists of documents tabled. Around 85% of EU laws had been agreed at first reading in the previous legislature, up from 29% two terms earlier, across more than 1,500 trilogue meetings, according to her office. "It is difficult to find out when trilogues are taking place, what is being discussed and by whom," O'Reilly said.

The General Court went further on March 22, 2018. In De Capitani v Parliament (case T-540/15), it annulled Parliament's refusal to release the fourth column of trilogue tables requested by Emilio De Capitani. Trilogues are a decisive stage of the legislative process, the court held, and no general presumption of secrecy covers ongoing negotiations.

By the 2019-2024 term, every file was agreed at first or early second reading, according to Parliament. Conciliation has effectively fallen out of use.

Why it matters for the advertising industry

For advertisers and ad tech vendors, the trilogue room is where the operative wording of EU digital law is fixed. Proposed on January 25, 2012, it went through Parliament's first-reading vote in March 2014 and a Council general approach on June 15, 2015, before trilogues under the Luxembourg presidency closed on December 15, 2015. Because Parliament had already voted, the deal was adopted as an early second-reading agreement in April 2016. The GDPR has applied since May 25, 2018.

The French presidency closed two platform files in 2022. The final trilogue on the Digital Markets Act, with Andreas Schwab as Parliament's rapporteur, was held on March 24, 2022. The Digital Services Act (DSA), which bans ads targeted at minors and ads profiled on sensitive data, followed on April 23, 2022. The AI Act deal came on the night of December 8, 2023 under the Spanish presidency, after roughly 36 hours of talks, according to Taylor Wessing.

Political advertising followed the same route. The Commission proposed the regulation on November 25, 2021 and welcomed the political agreement on November 7, 2023. Regulation (EU) 2024/900 applied from October 10, 2025, with penalties of up to 6% of annual turnover. Google had already said it would stop serving political ads in the EU, and Meta halted political, electoral and social issue ads on October 6, 2025.

Trilogues can also fail. The ePrivacy Regulation, published on January 10, 2017, would have moved cookie consent into browser settings. Parliament adopted its mandate in October 2017; the Council needed until February 10, 2021. Trilogues then opened and never closed. In February 2025 the Commission withdrew the proposal after eight years, citing no foreseeable agreement.

Secrecy, speed and who gets heard

Transparency remains the central complaint. Four-column documents are not proactively published while talks run, and Council texts marked LIMITE reach the public mainly through leaks to Politico or noyb, the privacy group chaired by Max Schrems. Critics argue that organisations with dense Brussels networks see drafts long before citizens do. Defenders, O'Reilly among them, accept that legislators need "political space" to negotiate and credit trilogues with efficiency.

A second criticism concerns democratic depth. A handful of negotiators decide the package, and plenary typically approves it as a whole.

Presidency calendars add pressure. The Belgian presidency pushed to close the GDPR procedural regulation by summer 2024, producing what noyb called a "half-baked" Council position. Schrems described the file as "the biggest legislative mess I have seen in a long time".

Not the same as

Conciliation Committee. A formal body under Article 294 TFEU, convened after a failed second reading, with equal numbers of Council and Parliament members and six weeks, extendable to eight, to agree a joint text. Trilogues prepare its meetings, but the committee itself is now rarely convened.

First-reading agreement. An outcome, not a meeting. Parliament adopts the trilogue compromise as its first-reading position and the Council approves it unchanged. An early second-reading agreement, as with the GDPR, is the variant used when Parliament has already voted.

Comitology. Committees of member state experts that oversee the Commission's implementing acts under Regulation (EU) No 182/2011. They operate after a law is adopted, not during its negotiation.

Recent developments

The Commission's Digital Omnibus, prepared through a call for evidence in September 2025 and proposed on November 19, 2025, split into two tracks with very different fates. The AI track moved fast. Parliament's internal market and civil liberties committees backed fixed 2027 and 2028 deadlines by 101 votes to 9 on March 18, 2026. Overnight talks in late April ended without agreement, but negotiators under the Cyprus presidency reached a provisional deal on May 7, 2026. Regulation (EU) 2026/1744 entered into force on July 27, 2026, according to Hunton Andrews Kurth.

The data track, which rewrites parts of the GDPR and cookie rules, has not reached trilogue. National data protection authorities opposed the narrowed personal data definition in February 2026, after the Netherlands raised formal concerns and the French ad industry called for the browser-signal clause to be deleted. On June 18, 2026 a Council compromise removed Article 88b, the clause obliging sites to honour browser consent signals. A September 3 text from the Irish presidency struck the unconditional right to object from the AI clause, and 19 groups wrote to co-rapporteurs Marina Kaljurand and Aura Salla seeking its return. A Coreper vote on the Council mandate, due on October 7, 2026, was postponed under pressure from Germany and France, according to Agence Europe. As of October 2026, the cookie and AI-training provisions advertisers care most about still await their trilogue.

Timeline

  • November 1, 1993: Maastricht Treaty enters into force, creating the codecision procedure
  • May 1, 1999: Treaty of Amsterdam allows codecision files to conclude at first reading
  • June 13, 2007: Parliament, Council and Commission sign the Joint Declaration on practical arrangements for codecision
  • December 1, 2009: Treaty of Lisbon renames codecision the ordinary legislative procedure
  • January 25, 2012: Commission proposes the GDPR
  • December 15, 2015: Final GDPR trilogue reaches agreement under the Luxembourg presidency
  • July 12, 2016: European Ombudsman issues trilogue transparency recommendations in inquiry OI/8/2015
  • January 10, 2017: Commission proposes the ePrivacy Regulation
  • March 22, 2018: General Court rules in De Capitani v Parliament (T-540/15) that trilogue documents are not presumptively secret
  • February 10, 2021: Council adopts its ePrivacy mandate, more than four years after the proposal
  • March 24, 2022: Final Digital Markets Act trilogue
  • April 23, 2022: Provisional agreement on the Digital Services Act
  • November 7, 2023: Commission welcomes agreement on political advertising regulation
  • December 8, 2023: AI Act provisional agreement after roughly 36 hours of talks
  • February 2025: Commission announces withdrawal of the ePrivacy Regulation
  • November 19, 2025: Commission proposes the Digital Omnibus
  • May 7, 2026: Provisional agreement on the Digital Omnibus on AI
  • June 18, 2026: Council compromise removes Article 88b browser consent signals
  • July 27, 2026: Regulation (EU) 2026/1744 enters into force
  • October 7, 2026: Coreper vote on the Digital Omnibus data mandate postponed

Summary

Who: Negotiating teams from the European Parliament (rapporteur, shadow rapporteurs and committee chair), the Council of the EU (the rotating presidency acting on a Coreper mandate) and the European Commission, which defends its proposal and drafts compromises.

What: Informal three-way negotiations, not mentioned in the Treaties, that produce a provisional agreement on the final text of EU legislation under the ordinary legislative procedure, worked through a four-column document.

When: Informal contacts began in the early 1990s after the Maastricht Treaty created codecision in 1993. Trilogues moved to first reading after the Amsterdam Treaty in 1999 and were endorsed by the June 13, 2007 Joint Declaration. In the 2019-2024 term every file was settled at first or early second reading.

Where: In Brussels and Strasbourg, behind closed doors, with documents released only on request following the General Court's March 22, 2018 De Capitani ruling.

Why: Parliament and the Council must adopt identical text, and formal readings are slow. Trilogues compress that process, which is why the GDPR, DSA, DMA, AI Act and political advertising rules were all settled there, and why the Digital Omnibus cookie and AI-training provisions will be.