The last film directed by Karl Ritter during the Third Reich. After BESATZUNG DORA was banned in 1943 due to changes in the war situation, the director was relegated to duties at the Uƒa film studio such as overseeing their young actors' program, producing films directed by others, and was given this harmless comedy of errors to direct, when the war in the years 1943–1945 needed top quality propaganda films more than ever......

Film author Frank Noack, who has written important biographies on both Veit Harlan and on Emil Jannings, wrote an article on Karl Ritter. Noack found Ritter's  propaganda films both crude and distasteful, then he had this to say about SOMMERNÄCHTE:

" What a surprise, then, to discover Sommernächte (Summer Nights), made in the summer of 1943 and released one year later. Its atmosphere resembles that of Käutner's Unter den Brücken. The credits already suggest an idyllic mood, with images of a lake at dawn, and one is further intrigued by an unusually ambitious score by Arnold Schönberg pupil Winfried Zillig, with orchestrations one doesn't hear in other films of the era; there even are some passages anticipating Bernard Hermann. The mood is admirably sustained. Another plus is the absence of process shots, particularly remarkable when people sit in a coach. Only those sequences set in a train compartment inevitably use process shots, and they are unobstrusive. The film as a whole defies definition. Ritter has directed a serious comedy, sensual and mature, opening with views of Berlin's inner city that was bombed at the time of release. René Deltgen plays a doctor who goes to a summer resort in order to catch fish, and, it is implied, to recover from bouts with the female sex. There is no evidence of war, nor is the film set in the past. Potentially gross humor, such as an eccentric old man urinating on the road, and two boys secretly putting an egg behind him, making him believe he himself had laid it - are realized with restraint. With his brutish charm and habit of running around shirtless, Deltgen is a most unusual romantic lead; as he got older, he would increasingly be cast as a villain, and not surprisingly he had been considered for Jud Süß. Somebody in the film describes him as "dark, very dark", and he is not even a patriot for in one scene he cites a French poet. As the woman who falls in love with him, Suse Graf is remarkably modern, resembling such leading ladies as Carola Höhn and Heli Finkenzeller. Intelligent and independent, but not aggressively so, she has studied at Lausanne and now spends her holidays alone, without such explanations as a failed love affair or fear of people. Ritter and his cinematographer create a paradise for these two; they meet on a lake, talk ever more intimately and begin to kiss, and all of a sudden she rises up, saying "I'm married." This comes as a shock and must have been particularly shocking to German soldiers watching the film in 1944. This woman is deceitful, and the film treats her sympathetically. We soon learn that she has lied, that she wants to test Deltgen. Her theory is that, if he really loves her, he will steal her from her husband. Which makes her behavior even more problematic. Since Deltgen doubts her story, she asks her best pal Ernst von Klipstein to come to the country, pretending to be her husband. Now the situation is only a little bit less risky; to the village people it looks like merry wife swapping. Asked about the couple, Deltgen says: "I like them both." Having already stolen her scarf, fetishistically enjoying its smell, Deltgen at last spends a night with her in his cabin. The morning after, there is absolutely no feeling of guilt. When he refers to something she has said the previous night, she corrects him: "That night we hadn't talked at all." One conflict still hasn't been solved: the lie. Like Brigitte Horney in Viktor Tourjansky's Illusion, Graf is a capricious woman with a good character, a noble liar. She leaves the summer resort, and she and Deltgen meet again for the happy ending. Curiously, there is no talk of marriage. Ritter's interest in cinematography is evident throughout, but it is the emotional maturity that stays in the mind. Sommernächte is not the usual bawdy comedy about wife swapping. The mere fact that Graf is asexually befriended with attractive Klipstein makes one wonder, for a decent woman was supposed to know no man except her husband. Within the film, the platonic nature of their friendship is explained by Klipstein's preference for naive girls whom he can educate, whereas Graf is too independent-minded for that kind of union. "

We have 6 lobby cards, 9 press photos, and 2 behind–the–scenes photos of Karl Ritter at work on this  late war film.