Between the German invasion of Poland on 1 September 1939 and the Anglo-French declaration of War against the German Reich on 3 September 1939, the entire city (a total of 120,000 people) was evacuated, like other border towns as well. Until the arrival of the Wehrmacht troops mid-June 1940, the city was, for <answer>ten months</answer>, completely empty, with the exception of the garrisoned soldiers. The Jews of Strasbourg had been evacuated to Périgueux and Limoges, the University had been evacuated to Clermont-Ferrand.
How long was the city completely empty?
ten months