Could you clarify your question? Spanish, Italian, and French are all Romance languages, so are you asking on the premise that Spanish and Italian are more similar to each other than they are to French?

Modern French is based on the dialects of the north of France, de so-called "langues d'oïl'. In the southern part of France, the "langues d'oc" was spoken, which has more in common with Spanish and Italian. (Side note: the names are said to derive from the way 'yes' is being said in those languages)

It is like a family tree, all of these languages (French, Spanish and Italian) are Romance languages, all linked to the Latin language (the common grandmother). The Northern French dialect is more of a 'cousin' to Italian and Spanish, while Spanish and Italian are 'sisters'. The Northern French original language has many influences from other cultures, mostly Keltic ones.

With the Ordinance of Villers-Cotterêts (1539), French became the official language of France, at that time already a centralised country with Paris (in the north) as capital. That worked out good for the Northern French dialect, which was already spoken in Paris. So, basically, the French language derived from the Parisian language.

Of course, this is an explanation in a nutshell, but I hoped it helped.