The march in Paris on Sunday was called originally in honour of the dead at Charlie Hebdo’s offices. In the meantime the dead had become more numerous. By the time the marchers reached Place de la Nation yesterday many were carrying A4 print-outs reading ‘Je suis Charlie, je suis juif, je suis flic.’ In addition to three dead police officers, four Jewish French citizens had died in the kosher supermarket in Porte de Vincennes.

The mood among yesterday’s vast crowds was quietly upbeat and self-assured. We were all ‘Charlie’ and we knew we were marching in step. Occasionally you saw the name Yoav (son of the chief rabbi in Tunis who was killed in Porte de Vincennes) on a home print-out. Often, when the crowd passed the rows of police vans lining the route there was spontaneous applause. By the time participants arrived at the destination and solemnity was no longer in order, a group of Syrian oppositionists began chanting: ‘Je suis Syrien, je suis Charlie.’ There were large pencils everywhere in evidence, one mutating into a Kalashnikov, with a shoulder-butt and magazine clip. A desultory teenager – 15 at most – strolled beside his parents with a placard reading: ‘Culture murdered by barbarians.’ A niggling wind got up but the Place de la Nation was becoming a happy-sad party by the time I left, around seven. Everyone was Charlie, for a day.

In a brasserie a retired train driver, black, with a wrestler’s grip on Republican values, said how much it meant to her to come on the march. She remembered Réunion – her French ‘outre-mer’ homeland – as a successful, multicultural exception, where there were different times for eating and fasting, opening and closing, and separate, complicated meals in school and workplace canteens. It was a good system in Réunion, but she didn’t want to see the rot set in here, in metropolitan France. She was haunted by the attack on Charlie Hebdo.

So were the couple, originally from Algeria, with a placard in black felt-tip: ‘Je suis Charlie, je suis Ahmed’ on one side – Ahmed Merabet was one of the police officers killed on Wednesday – and ‘No to terrorism, No to state terrorism’ on the other. An IT worker and a psychiatrist, they felt impelled to march in solidarity with the dead, and in defiance of the killers. But the time for a proper conversation about identity in France was due. They hadn’t liked shuffling along behind Binyamin Netanyahu: the psychiatrist had two brothers who’d worked in Gaza as journalists and she was convinced of the Palestinian cause. Netanyahu has made the most of the killings and invited French Jews to perform aliyah. Seven thousand Jews left France for Israel in 2014.

I’d spent the previous evening with two lycée teachers. One, born to an Iraqi father, said that after the attack on Charlie Hebdo’s offices her philosophy students in Amiens had asked for an off-syllabus discussion. She suggested they think about the names for what happened on 7 January and whatever happens next. They talked about words like ‘terrorism’ and ‘Islam’ and who owned them. The other teacher, who works on the southern edge of Paris, had difficulty getting some of her students to observe a minute’s silence the day after the murders. About a third of her class are ‘Muslims’ and, as one explained, there was no minute’s silence when coalition forces killed civilians in Afghanistan or the Middle East, or children died in Syria. All her students seemed horrified and shocked by the killings – for most French Muslims this is a moment of deep foreboding – but they weren’t going out of their way to honour the dead.

France is pleased with itself after yesterday’s immense performance, but there was something more convincing and moving about the night of 7 January, when crowds gathered without ceremony to mourn and reflect. Tens of thousands came out in Place de la République in Paris and as Libération’s journalists mingled, they were hearing exactly what should have been on everyone’s mind at a time like this. ‘I’m frightened about what this is going to unleash in terms of extremisms, when really what we need is a lot of ties.’ ‘This is a free pass for prejudice and escalation. The danger is already here. We have to unite.’ On the eve of an identity nightmare, the instincts of French men and women flickered reassuringly like lights about to be restored after a power cut. But today there are still great swathes of obscurity and sooner or later, as we fumble in the dark, announcing our whereabouts in ever more strident, anxious tones, we’re going to mistake someone in the building for the person he isn’t.