Monaco succession crisis of 1918 of this event, pursuant to the clauses of the treaty of 17 July 1918." The French government at the time was still the Vichy regime. Louis II died on 9 May 1949. The Principality of Monaco passed to his grandson, Rainier III. In the absence of an heir male, the ducal titles of Valentinois and Estouteville became extinct in French nobiliary law. Before Rainier III married Grace Kelly in April 1956, he notified the French government of his plans; the French ministry of foreign affairs replied with a message of official congratulations. Count Louis de Causans is suing the French
Albert II, Prince of Monaco his father and died without lawful heirs, it would have triggered Article 3 of the 1918 Franco-Monegasque Treaty, according to which the Principality of Monaco would become a protectorate of the French Republic. Prior to 2002, Monaco's constitution stipulated that only the last reigning prince's "direct and legitimate" descendants could inherit the crown. On 2 April 2002, Monaco promulgated Princely Law 1.249, which provides that if a reigning prince dies without surviving legitimate issue, the throne passes to his legitimate siblings and their legitimate descendants of both sexes, according to the principle of male-preference primogeniture. Following Albert's accession, this law