Telling how Philippe Auguste demanded contributions for wall.
(rough translation)
In 1190, before his departure for the third crusade, Philippe Auguste (1165-1223) required the inhabitants to contribute
to the safety of the city by the construction of a wall of approximately 5km, completed about 1210.

This wall, ten meters high and crowned with crenellation, was provided with entrances of ten doors.

Limited to the west by the fortress of the Louvre, built to protect it in the first years from the 13th century,
in the east by the place de Grève, in north by les Halles marketplace, and the south by the Sainte-Geneviève borough,
it defined a capital of 250 hectares [about 600 acres]; from now on, the palace, the treasure and the archives
are fixed at residence there, even if the king does not always reside there.


It acts as the tentative first of union of the three Parisian districts: the "City", religious heart,
administrative and judicious, the "City", economic pole located around the ports of Right Bank, and "the incipient University", on the Left Bank.

http://www.philippe-auguste.com/uk/