Charlemagne's Francia splits along different lines
Here is a map of Frankish expansion into Europe in the Early Middle Ages:
First, note that the original Frankish homeland is not where modern France is. That is to say, the territorial expansion of the French state started from a place that is mostly not inside the borders of modern France. So it is definitely possible for France to have evolved in a different direction and occupy a different set of modern territory.
What actually happened
This is the 2 minute history version, so lots of truncation for brevity. Basically, Charlemagne split his empire three ways among three heirs. The split was east, center, west as shown:
The provinces have slightly different names as shown, but the general regions are the same. The problem with the split was that the middle kingdom got diverse territories that were not close to each other. Provence, Lorraine, and Italy were all relatively rich at the time, but not close to each other given the mountains in the way. However, the split did manage to separate the parts that had lots of Latin-speaking peasantry (modern France) from those parts with lots of Germanic-speaking peasantry (modern Germany).
These territorial divisions were reinforced in the Ottonian dynasty (from Otto I) where the power of the Holy Roman Emperor was re-introduced but only for the German and Italian parts. Over the next 200 years, the German and Italian bits became politically consolidated under the Emperors, while the Kings of France consolidated the French and Occitan speaking parts starting from the Capetian dynasty and Robert II of France.
By this time (c 1000 AD), the languages started to diverge, as many of the minor nobility in what was now the German-speaking parts were still German-speaking themselves, but the nobles of the French-speaking parts now spoke a form of Vulgar Latin which was becoming Old French. 200 years earlier in Charlemagne's time, most of the warriors were Franks and spoke Frankish (which was itself a Germanic language).
What to make different
I glossed over a lot, but the easiest way to make Munich speak French is to change where the Kingdom divides went. Going of the territories of the top map, have Charlemagne divide the kingdoms into Aquitaine-Burgundy (which evolves to be be Occitan speaking), Neustria-Austrasia-Swabia (which evolves to be French speaking) and Lombardy (which evolves to be Italian speaking). Now let the French speaking kingdom rise to power as both the French Kings and Holy Roman Emperors throughout the Middle Ages. Aquitaine-Burgundy get incorporated, just as they did in real life, but bits of Germany like Thuringia and Bavaria do to. The German speakers are restricted to Frisia and Saxony, where they are more or less like the Dutch.
Advance history accordingly, and see what happens!