Various forms of contact restriction have been adopted in response to the Covid-19 pandemic. Only recently, rapid testing appeared as a new policy instrument. If sufficiently effective, it may serve as a substitute for contact restrictions. Against this background we evaluate the effects of a unique policy experiment: on March 16, the city of Tuebingen set up a rapid testing scheme while relaxing lockdown measures-in sharp contrast to its German peers. Comparing case rates in Tuebingen county to an appropriately defined control unit over a four-week period, we find an increase in the reported case rate, robustly across alternative specifications. However, the increase is temporary and about one half of it reflects cases that would have gone undetected in the absence of extra testing.