Hai-Alarm am Müggelsee 2013 on netflix

A lifeguard at Lake Müggel has his hand bitten off and the marks indicate a shark attack. The lake is closed to the public by extending a local festival indefinitely while the city council thinks of what can be done to remove the shark. The public becomes restless having their lake closed for so long and come up with a plan to drive the shark from the lake with large quantities of beer.