One million people have signed an internet petition calling for an end to the European Parliament's monthly sessions in Strasbourg.
The regular Strasbourg shuttle is enshrined in an EU treaty
The parliament, which does most of its work in Brussels, pays 200m euros (£135m) annually for what many MEPs condemn as a "travelling circus".
European Commission Vice-President Margot Wallstrom praised the petition.
In 1992, EU leaders agreed that MEPs should hold 12 "plenary" sessions every year in Strasbourg.
The move means not only more than 700 MEPs but also their aides and numerous documents have to travel the 454km (280 miles) from Brussels to Strasbourg.
Politicians 'must act'
The "Oneseat" internet campaign was launched in June by Swedish MEP Cecilia Malmstrom.
But a decision to scrap the Strasbourg location would have to be made unanimously by the 25 EU member governments, and France is strongly opposed.
Gary Titley MEP, Labour leader in the European Parliament, said "one million European citizens have spoken - Europe's politicians now need to respond".
"Lip service will not be good enough. The EU wants citizens to engage - they have - and now the politicians must act.
"Strasbourg costs 200m euros a year - money which would be far better spent on investment in jobs or on more help for the developing world.
"We need to reform the European Parliament so it is more effective and is more trusted by people in the UK and all over Europe."
Ms Wallstrom told the Brussels website EUpolitix.com that "for the Commission it is very important to show that we are welcoming an initiative involving so many citizens as this does and that we are happy to receive it".
"We would have to look at what sort of formal possibilities and legal possibilities we have. In this case it is very limited, everybody knows that beforehand."
Parliament president Josep Borrell tried but failed to get the question of ending the Strasbourg sessions on to the agenda of the European Union summit in December.
In April MEPs postponed plans to buy the Strasbourg buildings, because of concerns that the city of Strasbourg had been inflating the rent.
The city's mayor conceded that the rent included a sum he described as an insurance policy, in case the parliament should ever decide to move away.