THE president of Ile-de-France region Mr Jean-François Carenco, mayor of Paris Mrs Anne Hidalgo, and the newly-appointed president executive director of Paris Transport Authority (RATP) Mrs Elisabeth Borne, attended a ceremony on June 1 to mark the start of preliminary works on the eastern extension of Paris metro Line 11 from Mairie des Lilas to Rosny-Bois-Perrier.