This poloshirt is a vintage piece from the 1970s, designed by the renowned fashion brand Christian Dior.
The Monsieur was their licensed goods for men in the 70's to early 90's. When LVMH bought the company they revamped it, and created Dior Homme which is the high end men's sector. It is designed by Hedi Slimane. The women's line is called Christian Dior.