Nearly 6,000 drivers in the City of Bern were flashed by incorrectly configured speed cameras.
The police say the cameras were catching the wrong people between September 12th and October 19th.
They say the problem was with the software. The new cameras had been cleared to use by the Federal Department of Metrology.
The system is not being used anywhere else in the country - and the malfunctioning cameras have been switched off.
All fines issued will be cancelled or repaid. Anyone affected will be getting a letter.