In the southwestern corner of place des Vosges, duck beneath the arch to find two beautifully decorated, late-Renaissance courtyards festooned with allegorical reliefs of the seasons and the elements. It's the back entrance to the aristocratic mansion Hôtel de Sully, built between 1624 and 1630. Since 1967 it has housed the headquarters of the Centre des Monuments Nationaux, responsible for many of France's historical monuments, and is normally closed to the public, but check the website for occasional guided tours.
In the northern courtyard look to the southern side for spring (flowers and a bird in hand) and summer (wheat sheaves); in the southern courtyard turn to the northern side for autumn (grapes) and winter, with a symbol representing both the end of the year and the end of life. In the second courtyard are symbols for the elements: on the western side 'air' on the left and 'fire' on the right, and on the eastern side 'earth' on the left and 'water' on the right.