Throughout the reign of Louis XVIII, and even more so under the reign of Charles X, the students strongly opposed the regime. The king's paternal rod found its expression in an ever more strict discipline. Despite everything, the students carried on working under the supervision of prestigious tutors, most of whom were former students of the École, such as Arago, Cauchy, Petit, Dulong and Gay-Lussac. But it was no surprise to see them side with the people of Paris in 1830.
On 29 July, fifty of them stormed out of the École and placed themselves alongside the rebels, whom they sometimes led and protected. The student Vaneau was killed during the capture of the Babylone barracks: the rebels were full of admiration and gratitude towards these young scholars who gave their lives for freedom.
Order was restored when Louis Philippe came to power, but his presence did not satisfy the ambitions for freedom that had been unleashed during the 1830 Revolution. The École returned to its military status, but the students continued to show opposition to the new regime, which dismissed them in 1832, 1834 and 1844. In 1848, the students were once again in the streets, but this time more as mediators and intermediaries between authority and the rebels. From February to June 1848, they worked on behalf of the provisional government. Once peace had been restored, they quietly went back to the École.