You could say that for every country that ever had colonies anywhere.
The British lost the Raj, the Americans lost the Philippines (if you want to count that as one), the Russians sold Alaska, the Spanish lost almost everything. I hope I'm taking it the wrong way, but your wording makes it sound as if mismanagement and loss of colonial holdings is a purely French invention.
No, certainly not. It just seems as if France never benefitted from its colonies, though maybe this is just the presentation of history. You're right that the US and Russia were pretty bad at it too. Britain voluntarily gave up the Raj eventually, after colonialism had finally been rejected by the worldwide community, whereas France simply fought losing battles in Algeria and Vietnam before losing what it had.
So nobody's going to respond to the more interesting question in my post, WI Vietnam is liberated freely (albeit under diplomatic pressure) by the French? Or should I start a new thread?