Extension of the RER E in Paris, a giant underground construction site in a "pocket handkerchief"

Construction site
Par Batinfo source: AFP
Porte Maillot works - Underground section - © SNCF Réseau Eole project management

A huge site in a "pocket handkerchief": Porte Maillot in Paris, underground work to extend the RER E juggle with multiple constraints, starting with the lack of space in an already very dense district.