As far as I'm aware the letter of the law is you can cancel with a formal letter (lettre recommandée avec accusé de réception), and that's the most bothersome i

As far as I'm aware the letter of the law is you can cancel with a formal letter (lettre recommandée avec accusé de réception), and that's the most bothersome it should ever get. They shouldn't have the right to ask that of you, and it's likely they're just taking advantage of people.