The project was supported by the old generation of generals such as Philippe Pétain who had lead the French Army through World War I and envisioned a rematch against Germany as a mostly stationary conflict, while it was criticized by the advocates of mobile warfare like Charles de Gaulle. Its performance was mixed when it finally was tested in the first stages of World War II: the strongest section in Alsace-Lorraine held the halfhearted German attacks back, but the French did not make use of it to push against the much weaker Siegfried Line built by the Germans, and Belgium denied pass through her territory to all belligerents until it was invaded by Germany several months later. In the end the Germans defeated the Allies in the Low Countries and pushed into France through the weaker fortifications south of Belgium and the Ardennes (a rugged, heavily forested area that the French high staff had wrongly considered "unpassable" by motorized forces) while avoiding the stronger section altogether. Thus, "Maginot Line" has entered the vernacular as synonym for some measure where much effort is put on only to fail spectacullarly.
The Maginot Line in The War That Came Early Edit
By 1938, the Maginot Line was widely famous though the world as the longest and most fortified line of defense in existence and had served as inspiration to both the Siegfried Line in Germany and the Czechoslovak Border Fortifications. People often said that, in the event of a new war against Germany, the Maginot Line would not just save France, but that it had to.
The Line wasn't attacked when France declared war on Germany in response to her invasion of Czechoslovakia. However, France failed to take advantage of this and limited herself to a half-hearted invasion of the Saarland that was withdrawn later without opposition, believing that the German defences were stronger than they really were. Later Germany avoided the stronger section and pushed into France through Belgium and the Ardennes instead until its advance was stopped almost miraculously at the gates of Paris itself, saving the Maginot Line's reputation in extremis.
In 1941, the French very quietly began extending the Maginot Line further west so that it aligned with German-occupied Belgium. Though France and Germany were purported allies at this time, the move would have been considered provocative by the Germans had they known of it.