The station, situated in the heart of the city and with approximately 540,000 daily users, was closed for renovation on August 21 and was due to re-open on December 19, Le Parisien reports.

But numerous construction hazards, including the presence of lead and asbestos, mean it is not due to be in use again until April 17 2023.

The €32 million (£27.5 million/$33.75 million) project, financed by Île-de-France Mobilités, aims to renovate and modernise one of the main "tourist" stations in the network before the Olympics scheduled start on July 26 2024.

"This extension of the duration of the work is due to the discovery of asbestos residues during the demolition of partitions and floors and traces of lead on certain metal structures", an SNCF site manager said.

"Asbestos is non-volatile and presents no danger to local residents, travellers and people working on the site, as well as traces of lead found in confined worksite areas.

"However, these two materials require the implementation of specific, fully controlled protocols to be fully removed in complete safety."

The delay has brought a strong reaction from Circule, the user group for regular patrons of the RER C.

"This operation is necessary but we are angry, because these site hazards were completely foreseeable," said the Circule head Maryvonne Noël.

"It is unfortunately a habit - none of the projects carried out by the SNCF on the RER C is ever finished within the announced deadlines."