They oppose changes that will lead to more in-school assessment of the exam because they fear this will give pupils from posh lycees the edge over those from inner-city schools. They are also worried about changes in the course and the proposed end of the bac's independent study project.
A February day in England. Hundreds of protesters turn out. Some are members of the Countryside Alliance who are outraged by the Government's decision to ban hunting. Others are outraged by the hunters. A Labour MP who supports the ban is pelted with eggs by hunt supporters.
The contrast is instructive. The French have no problem with hunting. About 10,000 French citizens pursue la chasse ... cour without a whisper of protest and the sport's popularity is growing. President Chirac, asked about the English hunting controversy during a visit last autumn, replied with a shrug: "I have no judgement to make on a great British tradition."
Equally, it is unthinkable that thousands of students or teachers on this side of the Channel would demonstrate over the issues at stake in this week's white paper on 14-19 education, although some of the territory it covers is similar to that which preoccupies the French. Yet there is a huge consensus among teachers and most education leaders against ministers'
decision to jettison the diploma proposed by Sir Mike Tomlinson, to preserve A-levels and offer less academic students a vocational diploma.
Even if ministers had taken a different view and decided that the A-level should be subsumed into a diploma, it is hard to imagine the educational equivalent of the Countryside Alliance (public school heads, Chris Woodhead?) waving their banners outside Parliament.
You can argue that the French will find any excuse for a demo. But the real reason for the difference is more uncomfortable. It is about the value the two countries place on education and the importance we attach to qualifications, either academic or vocational. One of our most intractable problems in England is persuading people that education matters.
Inspectors' reports complain of a lack of motivation of working-class boys.
Among developed countries, we have one of the highest drop-out rates from education at the age of 16 because thousands of young people think they can get on perfectly well in life with few qualifications.
This view runs throughout society. Margaret Thatcher agreed with the drop-outs. She liked to point out how many successful entrepreneurs had been failures at school or had never been near a university. Tony Blair has done better. His Government has tried to put education at the heart of its programme. In primary schools, it has made good progress with its insistence that most 11-year-olds should be able to read and write reasonably.
But this week's white paper is a backward step. Will teenagers be persuaded to stay on at school by a vocational diploma when the message from politicians is that the only qualification that really counts is A-level? Down with A-level. A diploma for all. I am sorry there will be no placard-waving demonstrators from the Educational Alliance on the streets of London.