César-Egasse du Boulay (died 1678), known as Bulaeus, was a French historian.
His main work is the Historia Universitatis Parisiensis, covering the period from the supposed foundation of the university by Charlemagne (800) to 1600.
The censors appointed by the king found nothing blameworthy in the work, and the last three volumes were published in 1673.
The 1913 Catholic Encyclopedia describes this history as "important on account of the many original documents which it reproduces", but criticizes the "poor judgment of the author."
Other writings of Du Boulay refer to the same topic of the university, its foundation, patrons, administration, and privileges: In addition to these Du Boulay wrote Speculum eloquentiæ (1658) and Trésor des antiquités romaines (1650).