When war was declared in September 1939, all of the Le Fantasques were assigned to the Force de Raid, tasked to hunt down German commerce raiders and blockade runners.

L'Audacieux and two of her sister ships were based in Dakar, French West Africa, to patrol the Central Atlantic for several months in late 1939.

They returned to Metropolitan France before the end of the year and were transferred to French Algeria in late April 1940 in case Italy decided to enter the war.

The turbines were designed to produce 74,000 metric horsepower (54,000 kW; 73,000 shp), which was intended to give the ships a maximum speed of 37 knots (69 km/h; 43 mph).

During her sea trials on 8 May 1935, her turbines provided 97,448 PS (71,673 kW; 96,115 shp) and she reached 42.4 knots (78.5 km/h; 48.8 mph) for a single hour.

After the war began, depth-charge stowage increased to 48 and a pair of rails were installed on the stern for 35-kilogram (77 lb) depth charges.

[6] The ship departed Brest on 4 December 1935 to represent the Marine Nationale at the celebration of the tercentenary of the French colonization of the Antilles where she joined the cruiser Emile Bertin and the submarine Surcouf in making port visits to Pointe-à-Pitre, Guadeloupe, and Fort de France, Martinique.

[8] During 21–30 October, the Force de Raid, including all of the Le Fantasques, screened Convoy KJ 4 against a possible attack by the heavy cruiser Admiral Graf Spee.

[10] L'Audacieux was one of the escorts for Strasbourg and her sister Dunkerque as the Force de Raid reassembled at Mers-el-Kébir, French Algeria, in late April 1940 in an effort to intimidate the Italians from entering the war.

After the British attack on Mers-el-Kébir on 3 July, the ship escorted the cruisers that failed to rendezvous with Strasbourg, which escaped to Toulon.

In response, the Germans and Italians authorized the Vichy French to send ships to the Gulf of Guinea to bring the rebellious colonies back under control.

The destroyers lacked enough range to reach Dakar at the 24 knots (44 km/h; 28 mph) ordered by Contre amiral (Rear Admiral) Célestin Bourragué and were forced to return to Casablanca.

[13] The French destroyers were tasked to make a continuous smoke screen to protect the cruisers as they maneuvered to avoid British shells.

The heavy fog reduced the ability of the French ships to spot the British and L'Audacieux was ordered to venture forth on a reconnaissance mission.