Yes it is a DeSoto Diplomat Custom of 1953 ( series SP-24).They were similar to the Plymouth but curiously still used the former lower compression ( 7,0 :1) Plymouth engine of 97 hp àf 1949-52 instead of Plymouths 7,1:1 100 hp engine of 1953.
That's a very interesting point, pilou. I recall reading that they used lower compression engines due to the generally poorer quality of fuel in some of the countries the Diplomats were exported to.