Complex sentence: In the 1920s, France, as the main supporter of the Little Entente, pursued its policy towards tightening the alliance by launching a series of friendship treaties aimed at forging the relations between France, Czechoslovakia, Kingdom of Serbs, Croats and Slovenes, and Romania.
Split into simpler sentences: In the 1920s, France as the decisive supporter of the Little Entente pursued its policy towards tightening the alliance. Hence this power launched a series of friendship treaties aimed at forging the relations between France, Czechoslovakia, Kingdom of Serbs, Croats and Slovenes, and Romania.