Anyone heard of a "french shampoo"?

I had my hair colored a dark reddish brown last time I was in and the next time I go in I want to bring it down to more of a coppery-gold. My stylist said that in order to do that she'd have to do a "french shampoo" to get some of the color out. Apparently it's more than just lathering up your head as she said it's kind of tricky.

I can't find anything on the internet about this. Does anyone know what is all involved?

I'm guessing its a bleach bath I've heard other stylist say that before but I could be wrong to. I don't care for the Peppermint scrub idea it sounds to aggressive on strands lol would that be like getting a sand paper massage on your skin??? lol Just my thought when I read Peppermint Scrub haha.