"Le Marais" is a historic Parisian district (and not administrative), situated in the 3rd and the 4th districts of Paris, on the right bank of the Seine. It is bounded on the West by the street Beaubourg, in the East by the boulevard Beaumarchais, in the North by the street of Brittany and in the South by banks of the Seine and boulevard Henri IV (hotels of Aumont, Beauvais, Chalon-Luxembourg in the South of the street Saint Antoine) today.
Madame Beauvais was the first lady-in-waiting of the Mother-Queen, but she also had the King's ear. Rumor had it that Catherine de Beauvais was in charge of Louis XIV's sexual education, and since in the XVII century all sex ed was hands on, the Sun King appreciated her effort. As for the Hotel de Beauvais I am showing you here, it could be understood as a sign of royal appreciation; the stone for its construction was diverted from the construction site of the Louvre.