In August, as tensions with Germany were again heightened, this time over territorial demands on Poland, the French and British navies discussed coordination in the event of war with Germany; they agreed that the French would be responsible for covering Allied shipping south from the English Channel to the Gulf of Guinea in central Africa.
To protect shipping from German commerce raiders, the French created the Force de Raid (Raiding Force), with Strasbourg and Dunkerque as its core.
The group, which was under the command of Vice-amiral d'Escadre (Squadron Vice Admiral) Marcel-Bruno Gensoul, also included three light cruisers and eight large destroyers, and was based in Brest.
British observers informed the French Navy that the German "pocket battleships" of the Deutschland class had gone to sea in late August, bound for the Atlantic, and that contact with the vessels had been lost.
On 2 September, the day after Germany invaded Poland, but before France and Britain declared war, the Force de Raid sortied from Brest to guard against a possible attack by the Deutschlands.
Upon learning that the German ships had been spotted in the North Sea, Gensoul ordered his ships to return to port after they met the French passenger liner Flandre in the Azores.
The Force de Raid escorted the liner back to port and arrived in Brest on 6 September.

By this time, the German raiders had broken out into the Atlantic, so the British and French fleets formed hunter groups to track them down; the Force de Raid was split, with Dunkerque and Strasbourg operating individually as Force L and Force X, respectively.
Dunkerque, the aircraft carrier Béarn, and three cruisers remained in Brest while Strasbourg and two French heavy cruisers joined the British aircraft carrier HMS Hermes, based in Dakar, French West Africa.
Strasbourg left Brest on 7 October in company with the destroyer Volta and a division of torpedo boats, meeting Hermes off Camaret-sur-Mer later that day.
The ships then steamed south to met the heavy cruisers off Casablanca, ultimately arriving in Dakar on 14 October.
The ships went on a patrol in the central Atlantic from 23 to 29 October, during which they captured the German merchant ship Santa Fe on the 25th.
Another sweep followed from 7 to 13 November to the west of Cape Verde; the ships found four Germans aboard a Belgian passenger liner and took them prisoner.
Other warships arrived in Dakar on 21 November to relieve Strasbourg; she left that day along with the cruiser Algérie and an escort of torpedo boats.
Ordered to return to Brest, it was feared that German aircraft had dropped naval mines in the harbor entrance, so the ships were temporarily diverted to Quiberon Bay until a search revealed no mines on 29 November.

Faced with increasingly hostile posturing by Italy during the spring of 1940, the Force de Raid was dispatched to Mers-el-Kébir on 2 April.
Strasbourg, Dunkerque, two cruisers, and five destroyers left that afternoon and arrived three days later.
The squadron was quickly ordered to return to Brest just a few days later in response to the German landings in Norway on 9 April.
The Force de Raid left Mers-el-Kébir that day and arrived in Brest on the 12th, with the intention that the ships would cover convoys to reinforce Allied forces fighting in Norway.
But the threat of Italian intervention continued to weigh on the French command, which reversed the ships' orders and transferred them back to Mers-el-Kébir on 24 April; Strasbourg and the rest of the group left that day and arrived on 27 April.
They conducted training exercises in the western Mediterranean from 9 to 10 May but saw little activity for the next month.
On 10 June, Italy declared war on France and Britain.

Two days later, Strasbourg and Dunkerque sortied to intercept reported German and Italian ships that were incorrectly reported to be in the area.
The French had received faulty intelligence that had indicated that the Germans would attempt to force a group of battleships through the Strait of Gibraltar to strengthen the Italian fleet.
After the Fr
In August, as tensions with Germany were again heightened, this time over territorial demands on Poland, the French and British navies discussed coordination in the event of war with Germany; they agreed that the French would be responsible for covering Allied shipping south from the English Channel to the Gulf of Guinea in central Africa. To protect shipping from German commerce raiders, the French created the Force de Raid (Raiding Force), with Strasbourg and Dunkerque as its core. The group, which was under the command of Vice-amiral d'Escadre (Squadron Vice Admiral) Marcel-Bruno Gensoul, also included three light cruisers and eight large destroyers, and was based in Brest. British observers informed the French Navy that the German "pocket battleships" of the Deutschland class had gone to sea in late August, bound for the Atlantic, and that contact with the vessels had been lost. On 2 September, the day after Germany invaded Poland, but before France and Britain declared war, the Force de Raid sortied from Brest to guard against a possible attack by the Deutschlands. Upon learning that the German ships had been spotted in the North Sea, Gensoul ordered his ships to return to port after they met the French passenger liner Flandre in the Azores. The Force de Raid escorted the liner back to port and arrived in Brest on 6 September.
By this time, the German raiders had broken out into the Atlantic, so the British and French fleets formed hunter groups to track them down; the Force de Raid was split, with Dunkerque and Strasbourg operating individually as Force L and Force X, respectively. Dunkerque, the aircraft carrier Béarn, and three cruisers remained in Brest while Strasbourg and two French heavy cruisers joined the British aircraft carrier HMS Hermes, based in Dakar, French West Africa. Strasbourg left Brest on 7 October in company with the destroyer Volta and a division of torpedo boats, meeting Hermes off Camaret-sur-Mer later that day. The ships then steamed south to met the heavy cruisers off Casablanca, ultimately arriving in Dakar on 14 October. The ships went on a patrol in the central Atlantic from 23 to 29 October, during which they captured the German merchant ship Santa Fe on the 25th. Another sweep followed from 7 to 13 November to the west of Cape Verde; the ships found four Germans aboard a Belgian passenger liner and took them prisoner. Other warships arrived in Dakar on 21 November to relieve Strasbourg; she left that day along with the cruiser Algérie and an escort of torpedo boats. Ordered to return to Brest, it was feared that German aircraft had dropped naval mines in the harbor entrance, so the ships were temporarily diverted to Quiberon Bay until a search revealed no mines on 29 November.
Faced with increasingly hostile posturing by Italy during the spring of 1940, the Force de Raid was dispatched to Mers-el-Kébir on 2 April. Strasbourg, Dunkerque, two cruisers, and five destroyers left that afternoon and arrived three days later. The squadron was quickly ordered to return to Brest just a few days later in response to the German landings in Norway on 9 April. The Force de Raid left Mers-el-Kébir that day and arrived in Brest on the 12th, with the intention that the ships would cover convoys to reinforce Allied forces fighting in Norway. But the threat of Italian intervention continued to weigh on the French command, which reversed the ships' orders and transferred them back to Mers-el-Kébir on 24 April; Strasbourg and the rest of the group left that day and arrived on 27 April. They conducted training exercises in the western Mediterranean from 9 to 10 May but saw little activity for the next month. On 10 June, Italy declared war on France and Britain.
Two days later, Strasbourg and Dunkerque sortied to intercept reported German and Italian ships that were incorrectly reported to be in the area. The French had received faulty intelligence that had indicated that the Germans would attempt to force a group of battleships through the Strait of Gibraltar to strengthen the Italian fleet. After the Fr
French battleship Strasbourg