This chapter explores the defence options available to economic operators in France and the UK against unilateral and extraterritorial sanctions, including unilateral sanctions issued by these two countries. It compares French and UK case law, exploring how courts respond to the development of unilateral sanctions. National judges have had the opportunity to rule on the application of blocking statutes and on the effects of these sanctions on contracts. In the absence of strong legislative instruments on which to base their decisions, courts and tribunals have had to be inventive in containing the effects of extraterritorial sanctions. This chapter highlights the low impact of blocking statutes and raises the question of the legality and scope of sanctions clauses. The contribution shows that a common core of procedural principles and fundamental rights is developing in national and European courts, even if they are not necessarily applied in the same way.