During the transition period, the Brussels I Regulation (recast) on judgments in civil and commercial matters will continue to apply. Following the transition period, if the EU and the UK reach an agreement, a new mechanism will replace the Brussels I Regulation (recast). In the absence of an agreement, each Member State’s national law will govern these matters. The UK could nevertheless ratify the Lugano Convention on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters in the same way as the EU, Switzerland, Norway and Iceland. The UK has also made the necessary arrangements for the Hague Convention of 30 June 2005 on Choice of Court Agreements to apply as of the end of the transition period. These instruments are, however, less effective than the current system in terms of streamlining cross-border procedures and ensuring legal certainty.

During the transition period, the Brussels II bis Regulation and European Regulation (EC) No 4/2009 on maintenance obligations will continue to apply. By the end of the transition period, the EU and the UK should have reached an agreement on new instruments. In the absence of an agreement, the UK is already party to a number of multilateral conventions that mirror EU legislation (Hague Convention of 1980 on the Civil Aspects of International Child Abduction and the Hague Convention of 1996 on the International Protection of Children). The UK also plans to ratify the Hague Convention of 23 November 2007 on the International Recovery of Child Support and Other Forms of Family Maintenance. However, some matters are not covered by the Hague Conventions and domestic law will therefore have to be applied. For instance, this concerns the rules for court jurisdiction in divorce matters or maintenance obligations, or the recognition and enforcement of marriage-related decisions

During the transition period, the European Regulation on jurisdiction, applicable law and the recognition of insolvency decisions will continue to apply. Following the transition period, a new mechanism could replace this regulation in the event of the EU and the UK reaching an agreement. In the absence of an agreement, national legislation will apply.

During the transition period, European regulations on the service of judicial and extrajudicial documents and the taking of evidence as well as the EU directive on legal aid will continue to apply. Following the transition period, 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. They 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 the end of the transition period will be enforceable in France under the EU law which governed them prior to withdrawal. Decisions handed down in proceedings instituted after the end of the transition period will be enforced in France on the basis of conditions to be determined as a result of an agreement between the EU and the UK on their the future relationship. In the absence of an agreement, decisions will be enforced in France pursuant to national legislation whereby a French court has to grant exequatur, after checking that they have been lawfully handed down and that they comply 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 them not only to apply English law but also to 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 the end of the transition period 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 instituted after the end of the transition period will be enforced in France on the basis of conditions to be determined as a result of an agreement between the EU and the UK on their the future relationship. If there is no agreement with the UK, 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.