STRASBOURG, (France): The eastern French city of Strasbourg was shaken awake on Saturday by a 3.9-magnitude earthquake, the strongest yet in a string of shocks caused by a now-mothballed geothermal project. The epicentre of the quake, which began at 5:00 am, was five kilometres (about three miles) below the surface, under the northern suburb of La Wantzenau, according to France's National Seismic Monitoring Network (Renass).

A 2.3-magnitude aftershock was recorded five minutes later. Both events were classified by Renass as "induced", or caused by human activity.

While the shocks were not thought to have done much damage beyond creating some cracks in people's homes, they have reignited controversy over the geothermal project, which was halted late last year after a number of seismic incidents.

"It was really strong this time," tweeted Alain Fontanel, one of the leaders of the opposition in Strasbourg's city council. "The whole house shook for a few seconds. Thanks to the sorcerers' apprentices of deep geothermal energy for this rude awakening."