In 1910 Lequis became Chief of Staff of the Thorn Governorate and promoted to Colonel in 1912 and Commander of the Engineers of the I Army Corps in 1913.[1] During World War I, he was initially chief of the general staff of the governorate of Poznań and from October 1914, he was chief quartermaster of the 2nd Army and in December 1914, he was promoted to major general.[1] In May 1916 he was appointed commander of the 104th Infantry Brigade and in November of the same year he took charge of the 12th Division.[3] In 1917 he was awarded the Pour le Mérite and, after successfully participating in the Battle of Caporetto, was awarded the Pour le Mérite with Oak Leaves.[4] In March 1918 he took part in the German spring offensive with his division and was promoted to lieutenant general in July. He was then made governor of Metz before returning to Berlin after the Armistice of 11 November 1918 was signed.
During the November Revolution, Lequis received the command of a general command named after him, with which he was supposed to restore order in Berlin within the OHL before the start of the Reich Congress of Workers' and Soldiers' Councils. However, the plans drawn up by Lequis and his chief of staff, Major Bodo von Harbou, for the front-line troops, including many Guards regiments, to enter Berlin were not carried out as planned or failed because most of the soldiers were striving to go home.[5] During the invasion of Steglitz, Lequis was sworn into the Weimar Republic by the government of Friedrich Ebert on behalf of his officers and men and temporarily acted as a military governance from Berlin.[6]
Lequis gained importance during the 1918 Christmas crisis where troops of the Volksmarinedivision billeted in the Berlin Palace and in the Marstall in Berlin at Christmas 1918. Lequis was entrusted with the Guards Cavalry Rifle Division to secure the government district. The sailors of the Volksmarinedivision intended to make the agreed handover of the castle to the government dependent on the payment of their wages, which were currently refused. On the morning of December 24, 1918, the castle and stables were opened fire upon by the troops of Lequis with military equipment. However, due to the support of the civilian population that had flocked to the area, the troops had to withdraw again. After Lequis gave a thoughtless newspaper interview after the crisis was settled, he was replaced by General Freiherr von Lüttwitz and promoted to an officer.[1] On June 23, 1919, he was taken over by the Provisional Reichswehr as leader of Reichswehr Brigade 8 in Upper Silesia and put in charge of border protection. After the Kapp Putsch, Lequis retired from military service on September 18, 1920. Three months later he was given the rank of General of the Infantry.[1]