I found this camo hat in with a bunch of Vietnam era stuff that included a '68 dated large brim boonie and a ARVN OD boonie.
I have had no luck IDing this one.
While I think it's French influenced I don't think it's French as it has no markings and french hats like the M49 are usually well ink-stamped inside.
I've seen what is said to be a ARVN Ranger hat of the same style and type of vents but it was of a different camo pattern.
It's also wool-lined with a vinyl sweatband.