LOL… who knows exactly what the trademark is?
In France there is a big supermarket chain – one of the largest in the world – called Casino. Who’s to say that they couldn’t pull the same stunt with regards to the French market?
Did Google ban “blackjack” across all your markets, or just France/Monaco? If the latter, I wouldn’t be too worried… LOL… just use “vingt et un” or any of the other French names/variations instead 