These next to statements are presumption, correct me if I’m wrong. The Franks where, undoubtedly, Germanic. The Frankish language was, undoubtedly, a Germanic language. How did this Germanic language morph into the French we know today? What re-latinized France after the carolingians and Franks (germans) faded away? Is there any major and or noticeable effect that Frankish has had on French that differentiates it from other Romance languages?
A more general question would be, how did the Franks (A Germanic tribe and later empire) morph into the French?
As stated elsewhere, it was mostly to do with the areas settled. France had been the Roman provinces of Gaul, and retained a significant Gallo-Roman population that mixed in with the Franks. The non Gaulish areas conquered by Charlemagne were primarily Saxon, but they had never been Romanized. When the kingdom split into Francia and Germania(HRE) the respective populace in each area retained much of it's character. The Roman areas of Italy and Spain developed similarly, with the local Latins taking moderate influence from their Germanic rulers.
This is particularly notable in Romania where the language remained Latin/Romance,despite being a pass-through for 1000 years of various invasions.