When he arrives on the construction site of the Basilica of Saint-Denis in 1846, the architect Eugène Viollet-le-Duc causes controversy about the restoration work made by François Debret. The disassembly of the spare is not the direct cause why Debret was put aside, but was a pretext.
Among the works undertaken by Jacques-Guillaume Legrand (1743 – 1818), he decides in 1806 to raise the nave floor to the forecourt level. To do so, he creates new stands thanks to additions to the pillars. It is possible that because of this, pillards had been weakened.
The next architect, Jacques Cellérier (1742 – 1814), builds a « ch½ur d’hiver » (choir) for the canons. Leaning against the medieval building work, the monument destabilizes the entire structure. François Debret will find a solution to it in 1834.
In 1937, the northern spare is struck by lightening. The damage is so important that the State Councilor Jean Vatout, president of the Conseil des bâtiments civils (Council of civil buildings) suggests to release money exceptionally to fix the tower. Works will start immediatly and will last four months (117 days precisely).
On the 14th of June in 1841, François Debret goes to the Commission des monuments historiques (Committee of Historial Sites) where he is being criticized. He is accused of using an appalling way of restoration. Louis Lenormant, his most violent accuser, says that Debret has ruined the first monument of France and requires Debret to be placed under administrative supervision without divulging the case fearing the loss of money contribution from the state.
A few days later, Jean Vatout, Prosper Mérimée and Louis Lenormant visit Saint-Denis to write a detailed report to the Secretary of the Interior. Even if they firmly criticize Debret’s work on decoration, they compliment the consolidation work of the northern spare supposed to be extremely difficult to achieve.
In 1842 and 1843, ‘hurricanes’ damage the stonework. On August, 19th in 1845, around 1 p.m., the Montville tornado, formed in the Seine-Maritime department, gets to Saint-Denis and destroys the northern tower.
A year later, Jean Vatout and members of the Conseils des bâtiments civils notice that the walls of the tower are falling apart and ask for the spare to be disassembled to avoid any destruction. Debret will start the work on March 6th, 1846.
Do the spare need to be rebuilt? That is a question asked just after its disassembling. The General Inspector Biet declares having not a precised opinion but preconize the demolition of the northern tower in the interest of the portal of Saint-Denis.
The Conseil des bâtiments civils shares this idea and orders the demolition of the upper section of the tower.
Yet, François Debret resigns! The 69 years old architect is tired and will pass away four years later. His resignation appears to be due to the constant critics against him. The spare revived the feud. In an article publised on February 10th in 1846 in the Constitutionnel, Prosper Mérimée writes, without naming him, that Debret demonstrated lack of experience and that the spare problem would not have never happened under the direction of a specialized architect.
Because Mérimée is not an architecture specialist, some art historians think that an "experienced architect" could have whispered these words and that it could be Viollet-le-Duc himself. Furthermore, the archeologist Adolphe Napoléon Didron participates to the movement against Debret in his articles in the Annales archéologiques, saying that there is no authenticity left in the basilica.
At the same time, Henri Janniard (1798 -1863), director of the architecture and public works journal, publishes a plea in favor of Debret ascribing the orginal construction to the failure of the northern tower.
Even if mistakes have been committed, it seems that this quarrel is in reality a confrontation between two trends. On the one hand, the young Inspection Générale des Monuments Historiques (General Inspection of national heritage sites) rather monarchist, created by François Guizot and directed by Prosper Mérimée, including students such as Viollet-le-Duc. On the other hand, the Institute, heir of the Academies of the Ancien Regime, close to the Empire, to which François Debret, nominated by Napoleon Bonaparte, belonged.
The Inspection générale des Monuments Historiques (General Inspection of Historical Sites) is created in 1830 by François Guizot. His mission is to classify and allocate fundings for maintenance and restoration. The first inspector is Ludovic Vitet who resigns in 1834. Mérimée will succeed him.
In 1837, the Commission Nationale des Monuments Historiques (national committee of historical sites) joins the Inspection Générale des Monuments Historiques. Its goal is to teach future architects working on monuments. In 1840, the committee publishes its first list counting 1,082 monuments including 934 edifices. The Basilica of Saint-Denis is one of the first monument being classified as Monument Historique.
The Institut National founded in 1795 gathers the Classe de Littérature and the Beaux-Arts. The latter becomes the Académie des Beaux-Arts in 1816. Its offers teaching, organize competitive examinations including the most renown prize of Rome. François Debret is elected head of the Académie des Beaux-Arts in 1825.
Because the work at the Basilica of Saint-Denis is the most important work in the 19th century, especially with the restoration of the stained-glass windows, everybody wants to be in charge of it.