Please help identify what uniform! Photo of my grandpa during WW2.

Hi, I'm trying to find info on my grand-father.
We know nothing about him, only that he served in the army during WW2 and was involved in Normandy in 1944.
But I want to make sure because I know nothing about it. I attached a photo of him (left) and two friends. They seem to be on a boat... I don't have much info he never talked about it. What uniform is that? Thanks!

 

Could they be Royal Marine commandos? Definitely British battledress, and the guy at the back looks to be wearing a cap comforter.

 

Welcome to the forum. What was your grandfathers name and date of birth? I can look at the British Casualty lists on Find My Past to see if he is mentioned there. Agree with Gordon, looks like British uniform. You might have to apply here to get his service record Get a copy of military service records: Overview - GOV.UK

 

His surname is Steinmetzer. First name is supposed to be Jean, but apparently some people called him Robert when he was younger so maybe he changed his name.
Date of birth is March 1st, 1924.

 

Found this photo here, where I can find similarities in #1 and the guy on the top right of my original photo. No.2 Commando panorama - numbered copy.

 

Trouble is that in the original pic, only the guy at the back with the cap comforter appears to be wearing a cap badge, and I can't see what it is.
He also appears to have collar dogs on his blouse, but I can't make those out either.
Where did your grandfather come from?

 

The name comes from French Lorraine and is rather common in eastern France.

 

Steinmetzer=Stonemason?
Ok, working on the assumption they're Free French, could the guy's collar dogs/capbadge be the Cross of Lorraine?

 

The only Steinmetzer I could find before my subscription ran out at Findmypast was for a Rodney W. Steinmetzer, but born 1923 and he signed up in Montana.