They may do and the photograph may have been taken on an official visit to a French port. It is however, the ship's crest that looks to be very British. HMS Shark (54S) - Wikipedia
A real conundrum. Crest certainly looks like HM Submarine Shark but the ratings aren't RN. RN ratings didn't wear striped shirts and the good conduct badges are on the wrong arm. I would have gone for French but as TD says no bobble on the cap. Dutch maybe? As one is armed they look like gangway security staff. Tim
Sadly, there is nothing on the back of the photograph to indicate place or date. The sailors look as if they are bored with hanging around, rather like bailiffs who have knocked on the door but cannot gain entry.
HMS Shark (i) (N 54) of the Royal Navy - British Submarine of the S class - Allied Warships of WWII - uboat.net She seemed to spend a good amount of time in the Med (around Malta) or in the North Sea, so possibly they are guarding the boat whilst in dock - was there a Military Police Naval?? - and hence their relaxed look/demeanour or perhaps they are Danish/Norwegian sailors TD
High Wood, It’s not the same crest as on the Wikipedia page you linked to. It looks too big for a RN submarine crest. RegarTom
There is indeed a branch called Royal Navy Police but it was only formed in 2007. Prior to that it was called the RN Regulating Branch. Major port areas would have a Naval Provost Marshal and under him would be the Naval Patrol. Ships had a Senior NCO called the Master at Arms with the number of Regulators under him dependent on the size of ship. Their duties though were the maintenance of discipline on board and ashore. Ship security was the responsibility of the ship's crew. Tim
Maybe this. Dutch submarine called HNMS Tijgerhaai (Tiger shark). HNMS Tijgerhaai (P 336) of the Royal Dutch Navy - Dutch Submarine of the T class - Allied Warships of WWII - uboat.net Tim
I guess we need some of our naval experts to define what type of U-boat or submarine it is Ah well done timuk, the gun area certainly seems to fit with the photos TD