In 1723, Joseph 1st Bonnier de Mosson commissioned the master ironsmith Catrix to enclose the chateau of the Mosson with these imposing railings of 3 panels fifteen metres long which, in the words of Maurice Chauvet, is like "a light transparent Spanish fan concealing the charms and smiles of a Languedoc beauty". The original family, Bonnier de Mosson, were wealthy aristocrats, members of the academy of science and secretaries to the king, who ruined themselves by building their chateau and so sold the railings to the city of Montpellier to absorb some of their debts. They were first installed on the Government Square, now the Place de la Comédie, but the theatre there was destroyed by fire in 1785. It was then decided to enlarge the square and clean up that part of the town. The railings were no longer adequate and were put up for sale.
It was Jean Vassal, financial and development advisor and builder of Engarran, who bought the railings and installed them where they now are. The prize of each family to have occupied Engarran, they were listed as a historical monument on 31st May 1926. Now they seem proud to be the "Grill Railings"