Completely renovated in 2000 by Swiss architect Hervé Dessimoz, Tower W, formerly Winterthur, consists of a central reinforced concrete core. Designed according to the same principle as its neighbor Franklin, it is, with its 32 floors, the smaller of the two twin towers.

Winner of the Second Grand Prix de Rome in 1957, Jean-Robert Delb was commissioned to build this tower in 1974. Designer of numerous office buildings, Jean-Robert Delb founded his own agency in 1961.

After several collaborations in France and Morocco, he became particularly active in western Paris. He designed numerous office buildings and was also the architect of one of the largest residential towers in Paris: the Bourcy Tower in the 18th arrondissement. In partnership with Michel Chesneau and Jean Verola, the architect designed four towers in La Défense in the 1970s: W, Franklin, Atlantique, and Europe.