A franceman
A person who’s not French but acts like they are, even when they’re clearly not and probably don’t know how to eat a croissant.
He said he was a Franceman because he once tried to eat a croissant and it didn’t work out.
She told her friends she was a Franceman, even though she couldn’t spell ‘French’ and hated wine.
He claimed to be a Franceman just to impress his ex, even though he didn’t know what ‘bon appétit’ meant.