The five-day meeting will end on Saturday with the election of a new National Secretary, an updated title for the post of General Secretary, which Mr Marchais, 73, now occupies. Last year Mr Marchais announced that he would step down this month.
Named 'Jurassic Congress' by one former central committee member, the opening day in the Paris suburb of St-Ouen was a morose affair, reflecting the descent of the party to around 10 per cent of the vote since the crumbling of the Soviet empire, from its post-Second World War high of 30 per cent and the 20 per cent it could count on as recently as the 1970s.
Apart from the nomination of a new leader, thought to be likely to be someone in the same conservative mould as Mr Marchais, the party also planned to drop the notion of 'democratic centralism', by which the right to all democratic discussion was bestowed on delegates to such bodies as the central committee. As Le Monde said, even this decision, which has been on the party agenda for years, would be the result 'at least formally yet again of . . . centralism'. Various regional federations have already approved the necessary change of statutes by votes of between 80 and 99.5 per cent in favour, except in the Nord-Pas de Calais, where the reform was rejected. At the last congress four years ago, Anicet Le Pors, a minister in the 1981-84 Socialist government, tried to push through a motion abolishing the concept but failed.
One innovation yesterday was the absence of the usual long state-of-the-party speech by Mr Marchais. Summing up his 22 years at the head of the party in a radio interview, however, he said it had been a time when there had been 'positive aspects and also negative aspects'.
The formula was typical of a leadership which has consistently refused debate and has looked on helplessly as events in East Europe and the former Soviet Union removed the revolutionary model.
Guy Hermier, a Politburo member from Marseilles who is among leaders who have so far unsuccessfully sought internal reform, said the congress would not be 'that of the renovation which our times demand'. He said the party had been struck by paralysis for the past decade and Mr Marchais 'has his share of responsibility in all that'.
As for Mr Marchais' successor, the only consensus was that Mr Marchais would try to ensure that it would not be the only declared candidate so far, Philippe Herzog, 53, a reformist university lecturer.
Mr Herzog, once dismissed by Mr Marchais as 'a social democrat', said he had put himself forward as 'a provocation' to prompt debate among the 2,000 delegates. Other names included Andre Lajoinie, the party's candidate in the 1988 presidential elections, and Pierre Zarka, deputy editor of the party newspaper, L'Humanite.
In the absence of real change, the congress was likely to push the remaining dissidents who have tried to reform the party from within into the 'Big Bang' movement of Michel Rocard, the former Socialist Prime Minister and the most likely Socialist candidate for next year's presidential election.
Mr Rocard, now the Socialist Party's first secretary, and who has been trying to re-invigorate a left demoralised by the rout in parliamentary elections in March, has scheduled 'assizes of the left' for next month to which he has invited disillusioned Communists.