The existence of a fascist France could hypothetically lead to a German victory ITTL. Let's say that the French Republic is overthrown in coup circa. 1934 by a coalition of Right-Wing forces (including some army forces led by Petain or another Right-Wing general). Even a fascistic France would be reluctant to go to war with Germany, so it's possible that France reaches some sort of accommodation with Germany over the issue of Alsace-Lorraine. This isn't entirely fanciful - Hitler was willing to compromise with Mussolini on the subject of South Tyrol in exchange for Italy accepting the Anschluss. Going by that example, Hitler might drop his claims on Alsace-Lorraine to secure a peaceful frontier with France, which would allow him to pursue his ultimate goal - Lebensraum in the east without interference from the Western Allies.
Presumably, Alsatians in Alsace-Lorraine would be given two options: One is to stay in France and be assimilated; the other is to emigrate to Greater Germany. The Germans in South Tyrol were given this option, and the overwhelming majority of them (80%) elected to move to Germany. Considering how the Alsatians had never fully accepted their previous integration into Germany, it's unlikely that such a high percentage would elect to leave Alsace unless the French government was particularly aggressive in their attempts at Francization. Once Italy signs the Pact of Steel with Germany, chances are Italy would sign a separate set of treaties with France. Perhaps Italy would be allowed access to the Port of Djibouti, and maybe Tunisian Italians would be granted greater rights (they could also be given the option to emigrate to Libya or Italian East Africa). Italy may also receive free passage through the Suez Canal (provided that Britain agrees).
Come 1939 (if everything is still going on roughly OTL schedule), Hitler will invade Poland as his first step towards acquiring Lebensraum in the east. Britain will immediately declare war on Germany, but will be most unhappy when France refuses to follow up with a declaration of war of its own. Unless Churchill tries to bully France into joining the war, it's likely that the French State will remain neutral, freeing up large amounts of Axis manpower for eventual service on the Eastern Front and in the Balkans. I know I glazed over some things (what would Petain's France, for example, do when the Spanish Civil War takes place?) and perhaps oversimplified others, but this is just one possible scenario that played out in my head.