French and German police raided 24 homes in the two countries on Thursday, leading to the arrest of 15 suspected gang members and the recovery of 11 luxury cars, said Eurojust, which helped to coordinate the operation.
The investigation into the theft of posh cars started in June, when police dismantled a Roma camp in northern France, the Hague-based agency said in a statement.
That probe revealed links to two other cases lodged at the district court in Le Havre and it was discovered "the cars were stolen in France and sold to customers in Germany for low prices."
Seventeen cases were also under scrutiny by organised crime investigators in Lille, Eurojust said.
The car gang "broke into car owners' private homes to steal their car keys," before making off with the vehicles, forging identity papers and driving them to Germany, the agency said.