Sincere cooperation

This article is part of a series on
Politics of the European Union
Member states (27)  Austria  Belgium  Bulgaria  Croatia  Cyprus  Czech Republic  Denmark  Estonia  Finland  France  Germany  Greece  Hungary  Ireland  Italy  Latvia  Lithuania  Luxembourg  Malta  Netherlands  Poland  Portugal  Romania  Slovakia  Slovenia  Spain  Sweden Candidate countries Albania Bosnia and Herzegovina Georgia Moldova Montenegro North Macedonia Serbia Ukraine Countries with suspended accession negotiations Turkey Applicant countries Kosovo Special territories Belgium–Germany relations France–Germany relations Germany–Netherlands relations EU 3 Withdrawal from the European Union
Treaties and Declarations Schuman Declaration (1950) Treaty of Paris (1951) Europe Declaration (1951) Spaak Report (1956) Treaty of Rome (1957) Euratom Treaty (1957) Merger Treaty (1965) Solemn Declaration (1983) Single European Act (1986) Maastricht Treaty (1992) Treaty of Amsterdam (1997) Treaty of Nice (2001) Berlin Declaration (2007) Treaty of Lisbon (2007) Article 7 Article 50 Opt-outs Treaties of accession 1972, 1979, 1985, 1994, 2003, 2005, 2011 Treaties of succession 1984, 2020 Other treaties Schengen Agreement (1985) European Economic Area Agreement (1992) Abandoned treaties and agreements European Constitution (2004) UK membership renegotiation (2015–2016)
Executive institutions European Council President: Michel (ALDE) Parties List of meetings European Commission Von der Leyen Commission President: Von der Leyen (EPP) Vice Presidents College of Commissioners Civil Service Secretary-General: Juhansone
Legislative institutions Legislative procedure Council of the EU Presidency Hungary (July–December 2024) Configurations GAC FAC ECOFIN Eurogroup AGRIFISH EPSCO COMPET TTE ENVI JHA EYC Voting Secretariat Secretary-General: Thérèse Blanchet Directorates-general Council preparatory bodies COREPER Council Working Parties European Parliament (Members) President: Metsola Largest groups EPP (Manfred Weber) S&D (Iratxe García) Member of the European Parliament 9th session (2019–2024) Bureau Vice Presidents Quaestor Conference National parliaments
Judicial institutions Court of Justice of the EU European Court of Justice Members Advocates General Rulings General Court
Auditory institutions European Court of Auditors European Court of Auditors Other auditory bodies Internal Audit Service of the Commission Committee on Budgetary Control of the Parliament Economic and Financial Affairs configuration of the Council Anti-Fraud Office Public Prosecutor's Office
European Central Bank President Lagarde ESCB EMU Euro banknotes Euro coins
Other bodies European Investment Bank Group Investment Bank Investment Fund EIB Institute European Stability Mechanism European Stability Mechanism European University Institute European University Institute Unified Patent Court Unified Patent Court Agencies, decentralised independent bodies and joint undertakings Decentralised agencies of the EU Single market agencies CFSP agencies AFSC agencies ESFS European Supervisory Authorities SRM bodies Executive agencies of the EU Euratom agencies Decentralised independent bodies of the EU European Institute of Innovation and Technology European Public Prosecutor's Office Corporate bodies of the EU European Data Protection Board Authority for European Political Parties and European Political Foundations Joint undertakings of the EU of the Euratom Other independent bodies European Data Protection Supervisor European Ombudsman Advisory bodies European Committee of the Regions European Economic and Social Committee Political and Security Committee European Union Military Committee EU/ESA Space Council Inter-institutional bodies Publications Office of the European Union European External Action Service European Personnel Selection Office Anti-Fraud Office European Administrative School
Euratom Euratom members  Austria  Belgium  Bulgaria  Croatia  Cyprus  Czech Republic  Denmark  Estonia  Finland  France  Germany  Greece  Hungary  Ireland  Italy  Latvia  Lithuania  Luxembourg  Malta  Netherlands  Poland  Portugal  Romania  Slovakia  Slovenia  Spain  Sweden Associated states  Switzerland  United Kingdom Nuclear power in the European Union
Economic and Monetary Union Eurozone members Austria Belgium Croatia Cyprus Estonia Finland France Germany Greece Ireland Italy Latvia Lithuania Luxembourg Malta Netherlands Portugal Slovakia Slovenia Spain Eurogroup President Paschal Donohoe Other currencies in use Bulgarian lev Czech koruna Danish krone Hungarian forint Polish złoty Romanian leu Swedish krona ERM II Enlargement of the eurozone Non Euro countries relationship to Euro Bulgaria Czechia Denmark Hungary Poland Sweden Romania
Schengen Area  Austria  Belgium  Bulgaria  Croatia  Czech Republic  Denmark  Estonia  Finland  France  Germany  Greece  Hungary  Italy  Latvia  Lithuania  Luxembourg  Malta  Netherlands  Poland  Portugal  Romania  Slovakia  Slovenia  Spain  Sweden Non-EU members  Iceland  Liechtenstein  Norway  Switzerland Prüm Convention Schengen Information System Visa Information System Visa policy of the Schengen Area Non-Schengen area EU member states  Cyprus  Ireland (Opt-out)
European Economic Area EEA members Austria Belgium Bulgaria Croatia (provisional member) Cyprus Czech Republic Denmark Estonia Finland France Germany Greece Hungary Ireland Italy Latvia Lithuania Luxembourg Malta Netherlands Poland Portugal Romania Slovakia Slovenia Spain Sweden Non-EU members  Iceland  Liechtenstein  Norway Topics EEA Joint Committee EEA National Identity cards Microstates and the European Union
Elections Elections to the European Parliament European parties European foundations Political groups of the European Parliament Spitzenkandidat Constituencies Apportionment Referendums related to the EU European elections 1979 1984 1989 1994 1999 2004 2009 2014 2019 2024 (latest election) Elections in EU member states Austria Belgium Bulgaria Croatia Cyprus Czech Republic Denmark Estonia Finland France Germany Greece Hungary Ireland Italy Latvia Lithuania Luxembourg Malta Netherlands Poland Portugal Romania Slovakia Slovenia Spain Sweden
Law Acquis Primacy (ECJ Case 6/64) Subsidiarity Regulation Directive Decision Recommendation Fundamental Rights
Policies and issues Budget Customs Union Free Trade Agreements European Single Market Area of FS&J Policies Agricultural Energy Fisheries Regional Citizenship Passports of the European Union Identity Pro-Europeanism Euroscepticism European banking union European Banking Supervision Single Resolution Mechanism Capital Markets Union European System of Financial Supervision Integration Supranationalism European Federation Multi-speed Europe Enhanced cooperation
Foreign relations High Representative Josep Borrell Ext. Action Service Foreign Policy Defence Policy Foreign relations of EU member states Austria Belgium Bulgaria Croatia Cyprus Czech Republic Denmark Estonia Finland France Germany Greece Hungary Ireland Italy Latvia Lithuania Luxembourg Malta Netherlands Poland Portugal Romania Slovakia Slovenia Spain Sweden Argentina–European Union relations Armenia–European Union relations Australia–European Union relations Brazil–European Union relations Canada–European Union relations China–European Union relations European Union–NATO relations Georgia–European Union relations Iceland–European Union relations Kazakhstan–European Union relations Japan–European Union relations Mexico–European Union relations Moldova–European Union relations Norway–European Union relations Russia–European Union relations Switzerland–European Union relations Turkey–European Union relations Ukraine–European Union relations United Kingdom–European Union relations (History) Post-Brexit United Kingdom relations with the European Union Brexit United States–European Union relations Common Travel Area (Ireland) Microstates and the European Union European Union and the United Nations European Union Association Agreement G7 G20
Defunct bodies European Communities (1958–1993) European Coal and Steel Community European Economic Community European Community Western European Union Convention on the Future of Europe
European Union portal Other countries
v t e

In European Union law, sincere cooperation (Article 4(3) TEU) is one of the foundational principles of the European Union, which determines that the Union and the Member States are required to implement any necessary measures to guarantee compliance with the duties stemming from the Treaties "in full mutual respect".^[1][2]

Sincere cooperation is mentioned explicitly not only in the Treaty on European Union but also in the Court of Justice of the EU's case law, applicable to different exclusive, shared, supporting competences, such as the environment, the Area of Freedom, Security, and Justice, public health, competition rules governing the internal market, and others.^[3][4][5]

The jurisprudence of the CJEU has elaborated on four main responsibilities that derive from the principle of sincere cooperation:^[1]

1) An obligation for respect and assistance between the EU and Member States in attaining the Treaties' objectives

2) Member States have an active obligation to cooperate and comply with original and derivative European law

3) Member States need to refrain from taking any measures that would impede the aims and goals of the Union

4) Member States should facilitate the institutions of the EU to accomplish the Union's objectives.