Hello,
I am French and my wife is American US citizen. We got married in France with French marriage certificate, and so far we did not accomplish any admninistrative task in the US administration.

My wife needs to renew her passport and have her married showing in the new one.
Is it possible? How should we proceed?

Thanks in advance for your help!

You should visit the nearest US Consulate and fill out a passport renewal form; she will need two passport pictures, signed on the back by her and her marriage certificate. Basically the same format as applying for a passport.

Yes, there is nothing to do in the US if you did a legal marriage there to recognize the marriage.

She just needs to apply for a new passport and has her marriage license to prove