PHOTO: Chris Brown with fat tommy, When will he hit the gym again???

Chris Brown continues to look noticeably heavier since getting out of jail ... bravely partying without a shirt on while hanging out Wednesday afternoon in glorious St. Tropez.

CB is partying in France while one of his new neighbors in the San Fernando Valley tells TMZ he has no qualms about shooting the R&B singer if he trespasses onto his property.

Based on these photos, it doesn't seem Chris moves with a lot quickness these days ... so he's best to heed the warning.