To ask for the bill or check in French, you can say "L'addition, s'il vous plaît." Here's the pronunciation:
"L'addition, s'il vous plaît." [lah-di-syohn seel voo pleh]
In informal settings, you may also hear people say "L'addition, s'il te plaît" when addressing someone familiar or younger. However, when in doubt, it's safer to use the more formal "s'il vous plaît" as a sign of respect.