The Suffren class was an interwar treaty cruiser built by France for the French Navy.

The design was based on the preceding Duquesne-class cruiser and traded speed for protection while retaining the same armament.

[1] The following ships, Colbert, Foch, Dupleix, were completed to a modified design with heavier secondary armament and rearranged topside.

[3] The design of the Suffren was based on the Duquesne-class cruiser while maintaining the standard displacement of 10.000 tons.

The hull maintained the high freeboard with the raised forecastle of all post-war cruisers with excellent sea keeping qualities.

The hull design also kept the fine lines for the speed requirement complemented by the clipper bow with a gentle sheer and the marked flare keeping the forecastle dry even in heavy weather.

For Suffren and Colbert this space was filled with 500 tons of coal for the cruising boilers and therefore did not count against the standard displacement.

Reinterpreting the rules of the Washington Naval Treaty, the STNC decided to change and improve the level of protection on the next cruiser of the series, Foch.

[9] The last cruiser of the program, Dupleix, would be protected along the same lines as Foch, but with a slight increase.

Three single reduction gear Rateau-Bretagne steam turbines with six Guyot du Temple small tube boilers built by Indret rated at 20 kg/cm2 while operating at 215 °F (102 °C) would produce 90,000 CV[note 1] on three shafts to achieve a designed speed of 32 knots (59 km/h; 37 mph).

The aft boiler rooms and turbine would be inline driving the center shaft.

For Suffren and Colbert carried 640 tons of coal for the cruise boilers and would provide another 2,000 nm at 11 knots.

Starting with Colbert this was reduced to six;[16][17] the reduction was to be compensated by adding quadruple 13.2 mm Hotchkiss machine guns but these did not become available in quantity until the end of the 1930s.

[27][28] The catapults were modified to operate the Loire 130; this occurred in 1937 for Suffren[29] and shortly before the Second World War for the remaining ships.

[24] Following the completion of the Duquesne design, France learned that the Italian Trento-class cruiser incorporated 70mm belt and 50mm deck armour.

The 1924 Naval General Staff requirements for the next French treaty cruiser demanded greater protection while closely matching other characteristics of the Duquesne.

[32] Suffren replaced the cruiser Primauguet in French Indochina in July 1939[33] and remained until April 1940.

[35] Colbert, Foch and Dupleix performed wartime service in the Mediterranean and the Atlantic Ocean as parts of Force X and Y.

[36] On the night of 13-14 June 1940, they and the cruiser Algérie bombarded the Italian coast around Genoa as part of Operation Vado; little damage was done.