After WW1, France took several steps to prevent Germany from ever invading them again. What were two of them

In the 1919 Treaty of Versailles, the victorious powers (the United States, Great Britain, France, and other allied states) imposed punitive territorial, military, and economic provisions on defeated Germany. In the west, Germany returned Alsace-Lorraine to France.

Explanation:

because of that the declare war on each other