If you're keen to remove the romance I can recommend 'Marching with the Devil' by David Mason. It's a raw first-hand account of the Legion during the late 80s and describes the author's boyhood dream of joining vs the reality of his situation in the Legion.

https://www.goodreads.com/book/show/11683362-marching-with-t...

I was living in N’djamena, Tchad and there was a restaurant called Le Central on the main boulevard that officers from the Legion used to frequent. I was sitting at a nearby table finishing my bottle of Gala beer when they started to sing. I can’t remember the exact words, but it was one of the saddest laments that I have ever heard, essentially refraining that “I will die and you will never know my name. I fight, not for France, but for my brothers in the Legion.”

They had no romantic illusions about their service.

Funnily enough, the Legion étrangère is not a romantic thing at all in France. I have in fact always found it odd that it was even a topic, mostly for Americans to be honest.

I met a guy in 90s who went through it - hardly remember anything but a story from some remote jungle about a friend who was on a guard during night, and they found him headless in the morning. Suddenly the military didn't appear to this boy so much...

I remember reading that they were used to clean up the sites of French nuclear tests. Not very romantic...