February - Anglo-French discussions about Palestinian border resumed in London, but without Clemenceau who had been replaced by Millerand as French Premier. This made the negotiations somewhat more complicated because of the verbal nature of the December 1918 agreement between Clemenceau and Lloyd George, concerning the allotment of Palestine and Mosul to the British. Lloyd George attempted to use diplomatic persuasion to convince Berthelot that the British assumption of responsibility in Palestine was more of a burden than a privilege. He argued that, while the waters north of Palestine, according to the Sykes-Picot agreement, were unimportant for the welfare of Syria, they were essential to the prospering of Palestine. After two days of discussion Lloyd George arranged for another meeting between Berthelot and Lord Curzon. After three days of negotiation between the two men, Berthelot agreed to the Deauville line with this approval being conditional upon the approval of Millerand. It is suspected that he made this concession in exchange for increased French oil rights in Mesopotamia. However, Millerand had been issuing strong statements about his intention not to allow border changes, so his approval was not an assured fact.
March
April - At the San Remo Conference Berthelot announced French acceptance of the Deauville line as the border between Palestine and Syria. However the British seemed to have reconsidered their territorial ambitions since the February meetings and so announced that the final decision about the border location must await the approval of Emir Faisal, the man chosen to lead Syria under the French mandate. Berthelot was irritated at this British attempt to use Syrian nationalism so extort further border concessions from the French, but he agreed to postpone the final decision concerning the border of Palestine. And so the San Remo Conference awarded the Mandates for Palestine and Mesopotamia to the British and the Mandate for Syria to the French, but the exact boundaries separating these areas were not defined.
May
June - French public opinion turned against Britain because of Lloyd George's continuing demands concerning Palestine and Millerand rejected the concession made by Berthelot in February. The British tried to negotiate the inclusion of the Yarmuk River in Palestine, or at least secure irrigation rights to the river, but the French refused. They believed that had already made three unfavorable revisions to the Sykes-Picot Agreement without receiving anything in return and they were not willing to give in again. Members of the British government wanted to press the issue but the British diplomats knew that the situation was not promising and that Britain did not have much leverage in the situation. Zionists pushed the British government to ask for greater concessions from the French, but the French felt they had already given more than could be expected and so were intransigent.
August
September
October
November
December - A final conference was held between the British and the French at which time Lloyd George stated that he had made an agreement with Clemenceau concerning the borders between Syria and Palestine, the so called Deauville line, and that he was prepared to accept this line as the official border. Berthelot accepted the proposal and added that the French would give Palestine water rights for the upper Jordan and the Yarmuk river, and it was agreed that an international team would investigate the water supply issue in the area. The borders were finalized at a Anglo-French Convention on December 23, and these borders remain the legal boundaries between Syria-Lebanon and Palestine. A Boundary Commission determined the exact location of these boundaries and they went into effect after the signing of an agreement on March 7, 1923.