From May until October the "Gassenfreitag" takes place on the first Friday of the month in the Niederburg. The Niederburg is the oldest district in Konstanz. It is a small festival with foodstalls in front of the shops and bars.
It is a lovely little festival and very much appreciated by the locals. It is not very touristy and the atmosphere is lovely. Galleries, winebars and craft shops are open and serve food and drinks. Residents are allowed to set up flee market stalls in front of their homes.
Sneak into the shops as well. The party is on the street, ut when do you get the chance to visit the work shop of a violin maker for example?
Fr: 18:30-22:30