This issue of Superman, numbered #136, was published by Interpresse, S.A., a Belgian publisher whose products included French versions of American comic books like Superman. The cover shows a price for Belgium and for Canada, so I’d presume it was distributed in at least those two French-speaking countries. There is no month listed, but the interior has a copyright date of 1979.
The interior is full color and contains reprints of two Superman tales relettered in French: “My Best Friend, the Super-Spy,” originally published in Action Comics #449 in 1975, and “”Costume, Costume — Who’s Got the Costume?” from Superman #295, published in 1976.
The reason I bought this specific issue, though, is the use of a Superman The Movie promotional image featuring Christopher Reeve as Superman on the cover. I don’t really know for sure, but it looks like the image was originally black and white and then colorized and/or hand-separated so it could print in color.
I like photo covers a lot, and I don’t think DC ever put a photo of Christopher Reeve on the regular Superman series, so this is pretty unusual.