ロカルノ条約
At the risk of provoking a break-up of the UEBL, Pierre Prüm sought a rapprochement with France. When he had only just taken office, the prime minister was received in Paris. On 9 October 1925, an agreement was reached with the Direction Générale des Chemins de fer d’Alsace et de Lorraine. This agreement gave France the provisional right to the Guillaume-Luxembourg network. During the Prüm government's time in office, the Locarno Treaties were also signed. Although they came about without Luxembourgish participation, they marked an important date in the evolution of the Grand Duchy's defence policy. The fact that France and Germany guaranteed the inviolability of national borders, and agreed not to use war, consolidated Luxembourg's international situation. Pierre Prüm made use of Locarno Treaties' possibilities for international arbitration, to start talks with the Belgian and French governments. These would only conclude under the next government.