The polls continue to show that Socialist challenger Segolene Royal is tantalisingly close, but not close enough, to overtaking the ruling party’s Nicolas Sarkozy in Sunday’s presidential election in France. So, it was critical for Royal to do well in last night’s televised debate.

The debates have been a feature of French elections since the first Giscard-Mitterrand contest in 1974 — with the exception of the 2002 election, when President Jacques Chirac refused to debate the far-right’s Jean-Marie Le Pen.

In Australia, incumbent prime ministers and premiers have succeeded in shifting the televised debate (if they have one) to early in the campaign, when most voters are unengaged and even those who watch have plenty of time to forget it.

But in France, it takes place at the point of maximum impact — reflected in the estimated audience of 20 million people, almost a third of the population. So much for those who say we need compulsory voting to make people take an interest in politics.

Coming from behind, Royal needed to attack, while Sarkozy could be content, as one of Royal’s advisers put it, to play out time for a nil-all draw. And right from the start she took the offensive on such topics as crime, European unity, fiscal policy and the environment. (Summary and extracts from the debate in English are available here; see here for longer account in French.)

The debate ended up running half an hour over time, including towards the end an especially harsh exchange on education of disabled children, in which Royal said Sarkozy’s gap “between words and actions” was “the summit of political immorality”, and Sarkozy in turn accused his opponent of losing her temper: “To be president of the republic it’s necessary to be calm.”

Initial reactions suggest that Royal emerged ahead, but not with the decisive blow that her campaign needed. For what it’s worth, an online poll in Le Monde showed a clear majority thought Royal had won. It’s not unusual for French elections to be close; of the last four left-right contests, none has finished with a margin greater than 54-46. So Sarkozy will be happy if he can hold on to the lead of around 53-47 that the polls have been showing for the last week.

Royal could still make up the difference, but with only three days to go the betting has to be on Sarkozy.