Around 438 sharks dead sharks were found washed up on a beach in the French town of Pleubian in Brittany on Thursday.
The town Mayor, Loïc Mahé, said they were found trapped in a fishing net with stingrays and other fish.
The sharks were small, only measuring around 80cm.
After they were discovered, the town hall contacted the police, who cleaned up the dead animals with the help of volunteers.
The town hall was charged more than €3,000 for the cost of the removal.
The town's mayor then said he would press charges against the coast guards unless the suspect comes forward.
Mahé told the local press: "There were knives in the net, which means there was a maneuver to get rid of it."
The net was reported to be cut at both ends. The mayor added, "the net was a danger to navigation and diving" and an "irresponsible act."