French navy again ask for paying attention to the circulars dealing with submarines in waters where merchant ships were active according to the Dutch magazine Marineblad dated 1911-1912 no. 5

An item reported that the French minister of navy again pointed out to the circulars dated 5 July 1910 and 22 March 1911 dealing with the protection of submarines while executing exercises. On 22 March 1911 was ordered that the target ship for the submarines was to have a red flag in top. This ship was responsible to warn approaching merchant ships with the international signal MN (immediately stop). A launch or little vessel was to added to the target to bring the order or instructions to the merchant ship. One preventive measure was to exercise outside the common merchant routes. Further more was a policy developed in which for certain sectors near the main French harbours it was not allowed for submarines to move while submerged and merchant ships advised to use these sectors.