During a reannexation by Germany (1940–1945), High German was reinstated as the language of education. The population was forced to speak German and 'French' family names were Germanized. Following the Second World War, the 1927 regulation was not reinstated and the teaching of German in primary schools was suspended by a provisional rectorial decree, which was supposed to enable French to regain lost ground. The teaching of German became a major issue, however, as early as 1946. Following World War II, the French government pursued, in line with its traditional language policy, a campaign to suppress the use of German as part of a wider Francization campaign.

Between what time period did the reannexation of Germany occur?