Franco - Polish alliance ( 1921 ) The Franco - Polish alliance was the military alliance between Poland and France that was active between 1921 and 1940 . During the interwar period the alliance with Poland was one of the cornerstones of the French foreign policy . Near the end of that period , along with the Franco - British Alliance , it was the basis for the creation of the Allies of World War II . Background . Already during the France - Habsburg rivalry that started in the 16th century , France had tried to find allies to the east of Austria , namely hoping to ally with Poland . Poland ' s King Jan III Sobieski allegedly also had the intention to ally with France against the threat of Austria , but the greater threat posed by the Muslim - led Ottoman Empire made him fight for the Christian cause in the Battle of Vienna . In the 18th century , Poland was partitioned by Russia , Prussia and Austria , but Napoleon recreated the Polish state in the Grand Duchy of Warsaw . With the rise of a united German Empire in the 19th century , both France and Poland found a new common enemy . Interwar . During the Polish - Soviet War of 1920 , France was one of the most active supporters of Poland , and sent the French Military Mission to Poland to aid the Polish army . During the armistice , in early February in Paris , three pacts were discussed by Polish Chief of State Józef Piłsudski and French President Alexandre Millerand : political , military , and economic . The political alliance was signed there on February 19 , 1921 by Polish Minister of Foreign Affairs Count Eustachy Sapieha and his French counterpart Aristide Briand , in the background of the negotiations that ended the Polish - Soviet War ( Treaty of Riga ) . The agreement assumed common foreign policies , promotion of bilateral economical contacts , consultation of new pacts concerning Central and Eastern Europe as well as help in case one of the signatories is under " unprovoked " attack . As such it was a defensive alliance . The secret military pact was signed two days later , on February 21 , 1921 , and precised that the alliance is aimed at possible threats from both Germany and the Soviet Union . In case of aggression on Poland , the French would keep the communication lines free , and keep Germany in check , but was not required to send their troops or to declare war . Both political and military pacts were legally not in force until the economic pact was not ratified , which concluded on August 2 , 1923 . The alliance was further extended by the " Franco - Polish Warrant Agreement " signed October 16 , 1925 in Locarno , as part of the Locarno Treaties . The new treaty subscribed all previously - signed Polish - French agreements to the system of mutual pacts of the League of Nations . This alliance was closely tied with the Franco - Czech Alliance . The alliances of France with Poland and Czechoslovakia were aimed at deterring Germany from the use of force to achieve a revision of the postwar settlement or ensuring that German forces would be confronted with significant combined strength of its neighbours . Although Czechoslovakia had a significant economy and industry , and Poland a strong army , the French - Polish - Czechoslovakian triangle never reached its full potential . The Czechoslovakian foreign policy under Edvard Beneš shied however from signing a formal alliance with Poland that would force Czechoslovakia to take sides in the Polish - German territorial disputes . Czechoslovakia ' s influence was weakened by the doubts of its allies as to the trustworthiness of its army , Poland ' s influence was in turn undermined by the infighting between supporters and opponents of Józef Piłsudski . French reluctance to invest in its allies ( especially Polish ) industry , strengthening trade relations ( buying their agricultural products ) and sharing military expertise further weakened the alliance . In the 1930s the Franco - Polish alliance remained mostly inactive and its only effect was the French Military Mission to Poland , which continued to work with the Polish General Staff ever since the Polish - Soviet War of 1919 - 1920 . However , with the Nazi threat becoming increasingly visible , in the later part of the decade both countries started to seek a new pact that would not only guarantee the independence of all contracting parties but would also ensure military cooperation in case of a war with Germany . 1939 . Finally , a new alliance started to be formed in 1939 . The " Kasprzycki - Gamelin Convention " was signed May 19 , 1939 in Paris . It was named after the Polish Minister of War Affairs General Tadeusz Kasprzycki and the commander of the French Army Maurice Gamelin . It was military ( army - to - army , not state - to - state ) convention and was not in force legally , as it was dependent on signing and ratification of political convention . It obliged both armies to provide help to each other in case of a war with Nazi Germany . In May Gamelin promised a " bold relief offensive " within three weeks of German ' s attack . Finally the treaty became ratified by France on September 4 , 1939 , on the fourth day of German offensive on Poland . Despite all the obligations , France provided only token help to Poland during the Polish Defensive War of 1939 , in the form of the Saar Offensive . This is often considered an example of Western betrayal . However , the political convention was a basis of the recreation of the Polish Army in France in 1939 . In his 2012 book Pact Ribbentrop - Beck Polish historian Piotr Zychowicz provides the following description of the May 1939 negotiations between Tadeusz Kasprzycki and Maurice Gamelin : " After several Polish requests , and following lengthy negotiations in Paris , on May 18 French government with reluctance pledged to undertake military steps against Germany on the fifteenth day after the mobilization of their army . The French Army , however , stated that the agreement would not be valid without a political convention , and French government delayed signing it until September 4 . General Gamelin was surprised to see a Polish military delegation , headed by General Kasprzycki . Gamelin carried out negotiations in a way in which he avoided to make any concrete promises . He signed military agreement with revulsion , as in his opinion , the only country that mattered in Eastern Europe was the Soviet Union . When he found out that his government had refused to sign a political convention , he was delighted " . ( pages 280 - 281 ) Piotr Zychowicz quotes memoirs of French ambassador to Poland , Leon Noel , who as early as October 1938 wrote : " It is of utmost importance that we remove from our obligations everything that would deprive French government the freedom of decision on the day when Poland finds itself in war with Germany " . Georges Bonnet reassured Noel , writing that " our agreement with Poland is full of gaps , needed to keep our country away from war " . ( pages 279 - 280 )