Bonjour Myriam
There are some differences between the F4 and F3 that may be quite relevant to you. It is a big leap from a CB500 to an F4.
If you are considering an F4 you should definitely ride one before making a decision. The F4 has a fairly tall seat height, certainly relative to most sports bikes (although not tall like an adventure bike) and is about 20+ kg heavier than the F3. The F4 has an aggressive riding position and a tight turning circle, it could be difficult to manoeuvre unless one is tall enough and confident enough. I suggest that unless you are about 176cm or more, then an F4 might be a bit tall.
The F3 is more petite, a lower stand over height and lighter weight, and for mine just as much fun, and slightly less likely to result in you losing your license.
Other MV alternatives that are not sports bikes as such, are the Brutales, there are 4 and 3 cylinder variations, they are more practical than the F series bikes. As aesthetics and chilling is a priority for you, a Dragster might be just the ticket?
I can also recommend, and am very fond of Triumphs, they have twins and triples. You almost can't go wrong with a Japanese bike.
Please let us know what you end up doing.
Bon chance.
