Answer:
I was 80 francs richer before coming here.
Step-by-step explanation:
The comparative degree, as the name suggests, compares two things to show which has the lesser or greater degree of the quality stated. For instance, I can compare my height to someone else's: Mark is shorter than I am.
We are supposed to transform a sentence by using the comparative degree. The sentence is: But before coming here, I had at least 80 francs. Since we do not have the context in which the speaker says that, I will assume this person had at least 80 francs, but now he/she does not. Having that in mind, we can create the following sentence in the comparative degree:
I was 80 francs richer before coming here.