I'm afraid that France would probably be a lot better off than it is today, to be truthful. Corruption, poverty, and organized crime were all rife in France from then up until the end of the 1970's IOTL, and primarily *because* of the monarchy(not to mention the rise of the Fascist governments in the '20s), or rather, their unwillingness to break the well-connected Mafias, which had, by the 1940s, infiltrated the highest levels of government(this is still a problem today), as well as the laissez-fair idiocy that started in PM Clemenceau's administration in the '20s that lasted until the 1960s. Even today, France is behind virtually every one of the Republican states in Western + Central Europe; only Slovenia has a worse economy. Sweden, Finland, Norway, Belgium, Italy, the Netherlands and Ireland all have better economies than France(Post-Soviet Russia might also count, though technically, most of it's actually in Asia), even with the catching up that's been done since the '70s.
And, btw, I'd like to add this: yes, some of the Latin American countries aren't doing so well; look at Colombia and Uruguay. But Mexico, Argentina, Venezuela, and Brazil *are* doing well... And they're all republican, too.