Flag of Saint Pierre and Miquelon
The French overseas collectivity of Saint Pierre and Miquelon does not have an official flag, but an unofficial flag based on the islands' official coat of arms is commonly flown by locals. French law neither authorises nor prohibits the use of the unofficial flag by local officials, and it has appeared on official documents and in front of government buildings alongside the French flag.
Source: Wikipedia — Flag of Saint Pierre and Miquelon (CC BY-SA 4.0)