The ships received relatively minor modifications in their short careers; both ships received a funnel cap to reduce smoke interference with the command tower in 1938. After the start of World War II, the 12 m rangefinder for the forward main battery director was replaced with a version aboard "Dunkerque", while "Strasbourg" did not receive an updated rangefinder. A degaussing cable was fitted to "Strasbourg" to reduce the risk of detonating German magnetic mines during a refit from November 1939 to January 1940, and during another refit in August–September, a steel screen was erected to protect the light anti-aircraft guns from strafing attacks. "Strasbourg" had her command tower modified in November and December 1940 to refit her for use as a flagship, as "Dunkerque" had been disabled by that point. While "Dunkerque" was under repair at Toulon in 1942, consideration was given to replacing her aviation facilities with additional 37 mm guns to improve her anti-aircraft defences, but this work was not begun before the fleet was scuttled in November. During another refit from January to April 1942, "Strasbourg"s forward 37 mm mounts were moved from her forecastle to the weather deck, as they were on "Dunkerque", and she received an air-search radar set with four antennae. Early tests with the set indicated a detection range of .