Michael Glover Smith’s review published on Letterboxd:
Grand Illusion is a comedy and a drama, a war movie and a prison break film and, finally, thanks to an 11th hour appearance by the lovely Dita Parlo, a very touching love story. There is also a healthy dose of social criticism in the story of an aristocratic German Captain (memorably played by Erich von Stroheim) who shows favoritism to an upper class French captive, indicating that the bonds of class can sometimes be tighter than those of nationality. But this is just one of many examples of Renoir explicating the “arbitrary borders” made by man in one of the few films that deserves to be called a true anti-war movie.
From my Classic French Cinema Primer: whitecitycinema.com/2012/05/07/a-classic-french-cinema-primer-pt-1-beyond-the-tradition-of-quality/