This paper presents the design of an augmented reality visualization of the wall paintings (late 14 th century) of the Château de Germolles. This visualization is done through a mobile application, does not require any external equipment, and considers the co-lighting: the decor can thus be visualized under several virtual ambient lightings, simulating different seasons, weather conditions and two times of the day as well as candle lighting. We present the methods and models that have enabled these simulations, as well as their results and limitations. We also briefly discuss the limitation of an approach based solely on physical plausibility in relation to the objective of a visit speech.