You probably had an English patent? Since England is friendly with France, if you fire on French ships, your patent is removed, you see the ‘used item’ message and you are now considered hostile to the crown for firing upon their friends 🙂

Since you have a bounty with France, you should probably pay that off and avoid engagements with them until the diplomat’s work is complete and your relation with France gets resolved if you don’t want to lose your English patent.