My understanding is that much will depend on where both you, and your ex-husband are resident, and where (if you live in separate countries) you intend to introduce your divorce proceedings. I would have thought that the family lawyer in France (if you are resident in France, which is what I presume is the case from the details you give), would be the best placed to advise you.
French divorce law is complicated by any one’s standards, even if using the recently made available mutual consent option, especially if children are involved, or there is a history of domestic abuse.
One of the reasons (but not the only one) that Brexit has thrown a spanner in the works is that the UK is no longer bound by the Brussels 1 & 2 Convention regulations on the recognition and enforcement of judicial authority decisions within the EU, and has not signed up to the Lugano Treaty (unless that has changed recently the Lugano treaty is the international private law alternative of the Brussels 1 &2 Regs) . This means that French courts will be wary about allowing certain stipulations, or about the interpretation, of a divorce contract that might be litigated under a non-EU law system, and which might require subsequent enforcement in the UK, or with regard to a person and their effects that is not subject to the application of EU law.
My recommendation really would be to seek advice from someone that knows both French and UK divorce law.