The historical restitution of demolished buildings requires the use of many sources of different nature, but no physical evidence of the element to be restored. In order to overcome this difficulty, this article intends to propose the use of virtual immersion of experts in the reconstructed space. be restored. In order to overcome this difficulty, this article intends to propose the use of virtual immersion of experts in the reconstructed space. This immersion makes it possible to evoke conscious or unconscious comments, in the sense of sensible response, of body postures, which are all additional sources that can guide or inform a process of historical reconstruction. We take as an example the theatres of the Foire Saint-Germain in Paris in the 18th century - for which important historical documentation exists, but no archaeological remains - with the aim of proposing a first in Paris in the 18th century - for which important historical documentation exists, but no archaeological remains - with the aim of proposing a first draft of a methodology integrating the sensitivity of experts for a retro-architecture of these spaces. draft of a methodology integrating the sensitivity of experts for a retro-architecture of these spaces.