Sentence:  Nevertheless , Prokofieff was much influenced by Paris during the Twenties : the Paris which was the artistic <WSD>center</WSD> of the Western World - the social Paris to which Russian aristocracy migrated - the chic Paris which attracted the tourist dollars of rich America - the avant-garde Paris of Diaghileff , Stravinsky , Koussevitzky , Cocteau , Picasso - the laissez-faire Paris of Dadaism and ultramodern art - the Paris sympathique which took young composers to her bosom with such quick and easy enthusiasms . 
Meaning of the word marked with <WSD> tags:  an area that is approximately central within some larger region