Mr Sarkozy, the centre-right contender to take over from president Jacques Chirac, gave a much publicized speech in which he laid out his vision for Europe and how to revive the moribund EU constitution.

According to the blog 'Coulisses de Bruxelles,' French socialist MEP Gilles Savary said Ms Royal "does not wish to talk in a credible way on a subject of such importance in 30 minutes. She does not want to treat Europe lightly."

Mr Savary added that Ms Royal was caught out because "she did not know that Sarkozy would come to Brussels before her when the rendez-vous was made in June."

Mr Sarkozy on Friday proposed a new mini-treaty taking important elements of the EU constitution - rejected last year by French and Dutch voters - made suggestions for trans-national MEP lists and was clear that he felt Turkey should not become a member of the EU.

French socialists, however, remain deeply divided on the EU constitution and how to approach Europe. In the run-up to the referendum in May last year, the party almost tore itself apart on the issue. It ended up having an internal poll on the document, which many of the rank and file felt was too neo-liberal. The supporters of the constitution won the internal referendum but the issues and the emotions raised continue to resonate today.

Who gets to meet Mr Barroso?

If Ms Royal had come to Brussels and presented strong and detailed views on the future of the EU, it would have been major news at home as well as possibly bringing some of the socialist divisions on the issue once more to the fore.

The scheduled press conference with Mr Barroso had raised eyebrows anyway with questions as to what capacity she was seeing the commission president - she is president of the Poitou-Charentes region in western France.

Quizzed by journalists, the commission spokesperson said that Mr Barroso had granted her a meeting in her capacity as "an eminent personality of French and European political life."