A canton is an administrative local area, commonly a grouping of village, or a part a huge town. You could translate 'canton de Soissons' by something along the lines of 'Soissons council area'
Louis de Soissons was born in 1890.
de (french) = of (english)
De quelle? in French means "Of what?" in English.
Coup de grâce in French is "killing blow" in English.
Terrain de sport in French is "sports ground" in English.
Coup de la... in French means "blow of the..." in English.
Pas de soucis! in French means "No worries!" in English.
Compagnie de gestion in French means "management company" in English.
Pleins de bisous! in French means "Bunches of kisses!" in English.
Chaîne de montagnes in French means "mountain range" in English.
Qui est de Paris? in French is "Who is from Paris?" in English.
Café de l'amour in French means "coffeehouse of love" in English.