The scuffles in central Athens broke out when a group of several dozen demonstrators attempted to break through a police cordon set up on a major avenue as they headed toward the Finance Ministry.
The demonstrations by hundreds of union members were about job cuts and the government's ongoing austerity measures, and were unrelated to Gauck's visit. The German president met with his Greek counterpart earlier Thursday, a day ahead of a visit to the site of a World War II Nazi massacre in northwestern Greece.
Citing security concerns, authorities banned all demonstrations from 8 a.m. to 7p.m. local time in parts of central Athens. Several austerity-related protests, however, had already been scheduled.
Greece has been hammered by a vicious financial crisis since late 2009 that has developed into an economic depression. The country's economy has shrunk by around a quarter while unemployment has soared. Seasonally adjusted figures released by the statistics authority Thursday showed the jobless rate dipped marginally in December 2013 to 27.5 per cent from 27.6 per cent the previous month.
Since May 2010, Greece has been dependent on billions of euros in rescue loans from the other European Union countries that use the euro, and from the International Monetary Fund. In return, successive Greek governments have had to slash spending, increase taxes and enact wide-ranging economic reforms.
Germany is the largest single contributor to Greece's bailout, and one of the strongest proponents of the austerity agenda. Germany's stance has often been criticized in Greece has overly harsh, and has led to increasing resentment.
Gauck's three-day visit, which will include laying a wreath at the site of the World War II massacre in the village of Ligiades and a meeting with the Jewish community in the nearby town of Ioannina, has been seen as an attempt to dampen down on anti-German sentiment.