In the 1850s, the lighthouse underwent extensive restoration, during which the chapel’s stained glass windows were replaced. Julien Léopold Lobin (1814–1864), head of a glass painting workshop in Tours, was entrusted with creating Courouan’s stained glass windows. He specialized in the depiction of saints, but was also known for his painting skills, which he had acquired during a stay in Italy. Initially, the Sèvres Manufactory's glass painting workshop was to have been commissioned to do the work. However, at the start of 1855, the Manufactory announced that it was busy with a project that "would not be completed for several years…" and that as a result it could not accept the commission. Thus, on 9 March 1855 Lobin was hired by the Ponts et Chaussées administration to create a set of windows in double-layered glass, with each window secured by three bronze crossbars. The designs were based on models provided to him. Lobin agreed to have the stained glass windows installed by an "intelligent" worker and requested to be reimbursed for the cost of supplies, labour, transport and packing, as well as the transportation costs of the worker entrusted with installing the windows. His estimate came to 950 francs, and the new windows were installed on 1 August 1855.