Complex sentence: In July 1942 he took command of "1st U-boat Flotilla" in Brest, France, where he was captured after the city's surrender in August 1944, and was finally released in November 1947.
Split into simpler sentences: In July 1942 he took command of "1st U-boat Flotilla" in Brest, France. He was captured after the surrender of Brest in August 1944, and was finally released in November 1947.