Since January 1, 2021, the United Kingdom has been a third country to the European Union. EU law has ceased to apply in the UK.

The Brussels I and Brussels I (recast) regulations remain applicable for actions brought before 1 January 2021.

For actions brought on or after January 1, 2021, international instruments should be applied. The United Kingdom has taken the necessary steps to ensure that the Hague Convention of 30 June 2005 on choice of court agreements applies from the end of the transition period. In addition, the United Kingdom could ratify the Lugano Convention on jurisdiction, recognition and enforcement of judgments in civil and commercial matters, already ratified by the EU, Switzerland, Norway and Iceland. These instruments are nevertheless less effective in terms of simplification of cross-border procedures and legal certainty than the current system.

In the absence of an international instrument, it will be the common law of each Member State that will regulate this matter.

The Brussels II bis Regulation and European Regulation 4/2009 will continue to apply for actions brought before January 1, 2021.

For other procedures, reference should be made to the applicable international instruments. The United Kingdom is already a party to several multilateral conventions similar to EU law (the 1980 Hague Convention on child abduction and the 1996 Hague Convention on the protection of minors). The United Kingdom has also acceded to the Hague Convention of 23 November 2007 on maintenance obligations. However, certain matters are not covered by the Hague conventions and national law must be applied: this is the case, for example, of the rules of jurisdiction of the courts in matters of divorce or maintenance obligations, or of recognition and execution of judgments in matrimonial matters.

From 1 January 2021, domestic legislation will apply. However, for collective insolvency proceedings initiated before the end of the transition period, European regulations on jurisdiction, applicable law and the recognition of insolvency decisions will continue to apply.

From 1 January 2021, European regulations on the service of judicial and extrajudicial documents and the taking of evidence will no longer be able to be applied in legal proceedings if the request for mutual legal assistance is received  after 31 December 2020. These regulations will be replaced by the Hague Conventions which govern such requests but which do not allow direct cooperation in the same way as European instruments, and therefore lead to longer timeframes. 
European rules on legal aid will also be replaced by existing treaties (bilateral agreement and Hague Convention).

Decisions handed down in legal proceedings that were initiated prior to 1 January 2021 will be enforceable in France under the EU law which governed them prior to withdrawal.

Decisions handed down in proceedings initiated after 1 January 2021 will be enforced in France pursuant to the applicable international instruments, primarily the Hague Convention of 30 June 2005 on Choice of Court Agreements. In the absence of applicable instruments, decisions will be enforced pursuant to domestic legislation: a French court will have to grant exequatur, after checking that the decision was lawfully handed down and that it complies with international public policy.

The Paris Commercial Court and the Paris Court of Appeal have set up commercial divisions with judges who have a firm grasp of English and have perfect knowledge of English law. As a result, commercial litigation can be referred to them by requesting that they not only apply English law but also hold hearings in English, in the same manner as before English courts. The decisions handed down will be translated into English.

Legal proceedings or requests for cooperation which were initiated prior to 1 January 2021 will be subject to the EU legislation which was applicable to them prior to the withdrawal.

Requests for cooperation received or decisions handed down in proceedings initiated after 1 January 2021 will be enforced in France pursuant to the applicable international instruments.

Requests will have to be based, inter alia, on the Hague Convention of 25 October 1980 on the Civil Aspects of International Child Abduction, on the Hague Convention of 19 October 1996 on Jurisdiction, Applicable Law, Recognition, Enforcement and Co-operation in Respect of Parental Responsibility and Measures for the Protection of Children and, in respect of maintenance obligations, on the Hague Convention of 23  November 2007 on the International Recovery of Child Support and Other Forms of Family Maintenance.