Can extradition be refused if the French prison conditions are inadequate?

Yes, but the threshold is high. UK courts will refuse surrender where there is a real risk of treatment violating Article 3 ECHR — specifically inhuman or degrading conditions. French prison overcrowding has been raised in several cases, and European Court of Human Rights judgments have found violations in specific French facilities. Defence teams must present evidence identifying the likely detention facility and demonstrating systemic or individual risks. Courts may seek assurances from French authorities regarding conditions or specific prison placement. Generic concerns about the French penal system are insufficient; precise, evidence-based submissions are required.