The quake struck just before midnight and was centered in such a low area that significiant damage was avoided, the Swiss Earthquake Service reported. The center was 32 kilometers below the Albis mountain range between Zuger and Lake Zurich.
German neighboring regions of Lörrach, Konstanz und Waldshut-Tiengen were slightly affected, with some weak quake movements reported, a spokesman for the regional police in Freiburg reported.
However some alarmed citizens did call in. There have so far been no reports of property damage.
Just over the border in Switzerland, some 400 calls to local police were made from concerned citizens wondering what was going on. No reports of property damage have been made yet, local officials said.
The region's last earthquake was in October if 1997. It had a similar epicenter, way below the surface, but only reached a 3.2 level.