A ministerial statement warned of the unreliability of the abridged data. Newspapers had to sign a contract saying they would not publish “excessive simplification” in order to show the latest tables, out this month.

Education experts fear that annual tables giving school-leaving exam results for every lycee are being “misused” byparents anxious to get their children into the schools with the brightest pupils.

Since 1994 the education ministry has published a complex “value-added” measure which, as well as baccalaureat pass rates adjusts for factors such as strict selection by elite lycees; disparities between schools in deprived and privileged areas; pupils’ social origins; and the age they sit the exam, reflecting how many have repeated a year or more.

The result is a school in a disadvantaged suburb could score higher than a top Paris lycee. The aim is to provide clear information for families and enable heads and teachers to compare and judge their schools’ efficiency.

But some papers and magazines publish simplified annual “league tables” of the “best lycees” which give a misleading impression of many schools’ performance. Ambitious parents scrutinise the tables for the highest bac scores and use sharp tactics to secure places in prestigious lycees that ruthlessly cram and select pupils.

Schools in poor city areas, notably Paris, risk ghettoisation as parents of up to a quarter of local children find places elsewhere.

Education minister ClaudeAll gre has criticised newspapers’ tables and last September ordered heads to combat social segregation, reminding them that competition between schools was strictly forbidden. To the fury of many middle-class parents, allocation controls were tightened.

Headteachers complain the tables accentuate disparities and create a vicious circle; a school is stigmatised, leading to parents removing the ablest pupils, withdrawal of resources because of falling rolls, and deterioration of school results and reputations.

Interviewed in Liberation, which has stopped publishing the information, sociology professor Christian Baudelot, of the University of Provence, said the tables were “perhaps the best in the world”.

But, he said, the simplified versions “reinforce parental consumerism”. “Whether we want to or not, we attach most importance to schools which produce the brightest pupils,” he added.