At first the rails protruded above street level, causing accidents and problems for pedestrians. They were supplanted in 1852 by grooved rails or girder rails, invented by Alphonse Loubat. Loubat, inspired by Stephenson, built the first tramline in Paris, France. The line was inaugurated on 21 November 1853, in connection with the 1855 World Fair, running on a trial basis from Place de la Concorde to Pont de Sèvres and later to the village of Boulogne.