Celine Dion -- Rogue Cake-Eater Broke Into My Home!

Celine Dion was the victim of a fridge-raiding burglary yesterday, according to police -- after a man was arrested inside her Montreal mansion while munching on pastries ... and trying to take a bath.

According to CBS News, 36-year-old Daniel Bedard has been charged with breaking and entering, auto theft, and causing property damage -- after the man allegedly stole keys from Celine's husband's car ... and used them to break into the singer's house.

Bedard tripped the alarm in the process and police raided the home -- catching him while he was making himself a bath.

Laval police spokesman Franco Di Genova said, "He opened the water faucets, was pouring a nice warmish bath (and) he even managed to eat some pastry that was in the fridge."

Di Genova continued, "The suspect was coming down the big staircase and was asking: 'Hey, guys what are young doing here?'"