French rail operator SNCF has scrapped plans for a controversial expansion of Europe's busiest train station, the Gare du Nord in Paris, with the government urging Wednesday a "much smaller project" after cost estimates ballooned.

The overhaul would have tripled the size of the station -- site of the Eurostar terminal for high-speed trains to London, Brussels and Amsterdam -- before France hosts the Rugby World Cup in 2023 and the 2024 Summer Olympics.

The ornate 19th century facility already sees 700,000 people pass through every day.

But in July, the main contractor warned that the final bill would be triple initial estimates of 500 million euros ($587 million), with completion pushed back to 2025 at the earliest.

SNCF, which announced the decision late Tuesday, blamed the contractor Ceetrus -- a subsidiary of the Auchan supermarket chain -- of "serious failure" over the project.

"We have asked SNCF to study a much smaller project of around 50 million euros, to make improvements and meet the challenges of 2023 and 2024," Transport Minister Jean-Baptiste Djebbari told BFM television.

Ceetrus rejected the decision to drop the larger project, accusing SNCF of a lack of loyalty.

"I don't know what they're going to do with 50 million euros, apart from changing the windows and putting on a new coat of paint," Antoine Grolin, chairman of the Ceetrus board of directors, told AFP.

French and foreign travellers have long complained that the Gare du Nord is dirty and chaotic. 
French and foreign travellers have long complained that the Gare du Nord is dirty and chaotic.  AFP / Philippe LOPEZ

Transport Minister Djebbari also criticised Paris Mayor Anne Hidalgo -- a Socialist who is campaigning against Emmanuel Macron for the presidency in elections next year -- for opposing an expansion she had initially supported.

"This project was supported by Paris City Hall, voted for by City Hall, which then mounted an electoral campaign against it... there has been no political consistency on the matter," Djebbari said.

French and foreign travellers have long complained that the Gare du Nord, which also links Paris's high-density northern suburbs with the city centre, is dirty and chaotic.

But many residents of the multi-ethnic neighbourhood surrounding the station in northern Paris opposed a plan that aimed to turn it into a sprawling shopping and entertainment hub.

SNCF had vowed the expansion would improve the area by covering a large swath of the tracks with a garden esplanade and concert hall, along with shops and office space, while also renovating the Eurostar terminal.

It would have spread over 30 acres (124,000 square metres), more than triple the nine acres currently, to cope with traffic expected to reach 900,000 people per day by 2030.

Well-known architects including Jean Nouvel and Roland Castro had also slammed a "pharaonical" project, calling in an open letter last year for a "complete rethink".

SNCF said it would carry out a "quick adaptation" of the station "carried out in close concertation with everyone concerned."

"We are ready and willing to commit on a new renovation for Gare du Nord that serves users and fits with the urban landscape," Hidalgo's deputy Emmanuel Gregoire said in a statement.