Thanks for the interesting write up on this, likewise @edarsenal. I haven't seen the film yet but I definitely will sometime. I've just been doing some interesting research about it. Apparently Clément really went overboard building an accurate replica in the studio for the interior shots, and developed some interesting camera mechanics and filming techniques. Looking at screenshots it's interesting looking at the real life submarine you mention. It appears to be a French type of pre-war design, but with late/post-war additions such as the anti-aircraft emplacements, which make it look like a U-boat actually.
Research reveals that the boat in the script is U-471, an interesting choice considering the real life history there. U-471 was a German Type VIIC with a fairly unremarkable wartime record. She conducted three war patrols with no ships sunk, and was herself sunk in the port of Toulon during an air raid in 1944. However after the war the boat was raised and returned to service in 1946 with the French Navy as Millé, and served there until 1962 before being scrapped in '63. This and another boat of the same type apparently conducted their initial French Navy sea trials with German crews, who were still POWs at the time. I wonder if ideas of a similar escape ever crossed their minds? Look forward to seeing it.
Research reveals that the boat in the script is U-471, an interesting choice considering the real life history there. U-471 was a German Type VIIC with a fairly unremarkable wartime record. She conducted three war patrols with no ships sunk, and was herself sunk in the port of Toulon during an air raid in 1944. However after the war the boat was raised and returned to service in 1946 with the French Navy as Millé, and served there until 1962 before being scrapped in '63. This and another boat of the same type apparently conducted their initial French Navy sea trials with German crews, who were still POWs at the time. I wonder if ideas of a similar escape ever crossed their minds? Look forward to seeing it.
Sub used in the film
U-471/Millé in 1961