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(TMZ) - Cops were called to the Barbados house Sunday where Rihanna is staying -- presumably topless -- after a man trespassed onto the property.

Barbados Police tell TMZ  ... they received a call from someone in Rihanna's party after a man believed to be a German national wandered onto the private, beachfront estate.

By the time cops arrived, Mr. Beerfest had already beat a hasty retreat -- and we're told at no time was the singer in danger. 

Police say they don't believe the guy is a stalker, but they want to have a little chit chat with him ... in English.

Photo: Splash News