By Hugh Schofield
BBC News, Paris
The colleges prepare France's elite students for government
The French government's attempts to shake up the higher education system have run into opposition from the elite colleges known as the grandes ecoles.
The heads of the colleges are objecting to plans to open up their selection system by targeting students from poor backgrounds.
They say any such system would lead to a lowering of academic standards.
The 200 or so colleges have trained generations of French officials and administrators.
The grandes ecoles - which include such prestigious names as the Ecole Polytechnique and the Ecole Normale Superieur - see themselves as models of republican meritocracy.
In theory anyone with the right exam results can attend, thus gaining access to the country's governing class.
In practice, entry is largely limited to the sons and daughters of that very elite - the class, in essence, replacing itself through the generations.
Part of President Nicolas Sarkozy's political sales-pitch has been the need to break with just such institutions as this.
Last year, his government set an objective of having 30% of grandes ecoles students from poorer backgrounds - many of them, naturally under these criteria, to be from ethnic minorities.
The row broke out this week after the publication of a letter setting out why the heads of grandes ecoles disagree.
They say they want to keep the existing rigorous exam-based selection system, even though it clearly discriminates against youngsters who have not been to the right schools.