The French secular regime established appeared at the turn of late 19 th century and early 20 th century on the founding principle of the separation between state and church. This separation organized by the law of December 9 th 1905 has maintained since then. This article is questioning the reactions of the catholic Church facing this exclusion, that hit it very strongly, from the public sphere. It shows that the Roman institution has, throughout the whole past century, non remained in an unchanged posture. Two periods have followed. During the first length of time, it established a struggling relation with the republican state which lasted until the end of the third republic. Being nostalgic of the catholic state, it entirely rejected the "unfair secular laws". The second period established the church in a more open position : it acknowledged as legitimate the system of separation made by the 1905 law ; however it did not admit the principle of political subjectivity that it is based upon.