Resume : La Societe de legislation comparee fondee en 1869 par les avocats Paul Jozon et Alexandre Ribot, sous le patronage d'Edouard Laboulaye, marque le double projet scientifique et politique de contribuer a l'affirmation du courant liberal francais et a l'amelioration de la legislation en se nourrissant de l'etude des systemes juridiques, constitutionnels et judiciaires etrangers. « Pepiniere de senateurs inamovibles » selon Jean-Marie Mayeur et Alain Corbin, mais aussi de deputes, de ministres, d'ambassadeurs et de prefets, l'ancienne societe savante, est vite devenue une « boite a idees » liberale au cœur des rouages de la nouvelle Republique, a la conjonction des centres. Mots-cles : societe de legislation comparee – droit compare – think-tank – boite a idees – Alexandre Ribot – Paul Jozon Abstract : Compared Law Society was created in Paris in 1869 by two young lawyers, Paul Jozon and Alexandre Ribot, with the protection of Professor Edouard Laboulaye. The double aims of this scientific and political project were to contribute at the French liberal movement affirmation and both to make better laws by studying strangers jurisdictional and constitutional system and Law. Irremovable senators nursery, but also a candidate pool of members of Parliament, ministers, ambassadors and prefects, the primary scientific academy quickly turned into a liberal « suggestions box » at the very heart of the new republican public power, at the meeting point of left and right centers, gathering orleanism and opportunism. Key-Words : Compared Law Society – think-tank – suggestions box – Alexandre Ribot – Paul Jozon