Can France extradite me for conduct that occurred before Brexit?

Yes. The EU-UK Trade and Cooperation Agreement applies to extradition requests regardless of when the alleged offence occurred. French authorities regularly seek surrender for conduct predating the 2020 agreement. However, the timing may strengthen certain defences — particularly passage of time arguments if the alleged offence is historic and prosecution has been delayed without justification. Courts will assess whether the delay renders surrender unjust or oppressive, considering factors such as deterioration of evidence, the accused’s settled life in the UK, and any fault attributable to French authorities in failing to pursue the case earlier.