Of course, if you mention Saint-Denis to anyone in the centre of Paris they grimace. They know it is there and try never to go to it. With the exception of the Stade de France stadium there is little reason to go anywhere near the area. Having been scarred by waves of de-industrialisation and re-industrialisation, in recent years the government has attempted to do some social engineering, building municipal offices in the area for state employees to work in. But these employees (around 50,000) who have jobs in the area almost never live there. They come in from elsewhere in the morning and leave again in the evening, when their office blocks are carefully locked and the security fences secured. It is France’s immigration challenge summed up in one district.

The same phenomena can be witnessed in the suburbs of Marseilles and many other areas of France. But it can also be noticed by any visitor or resident, however unwilling to go to Saint-Denis, on a simple trip on the RER and Métro in the centre of Paris. Travelling on the deep underground RER, stopping infrequently and with long distances between stops, often feels like taking an underground train in an African city. Most of the people are black and they are making their way far out to the suburbs. Those places where the RER stops in Paris’s chic centres – Châtelet for example – are known as areas where there can be trouble, especially in the evening when bored youths from the banlieues hang around in town. Always there lingers the memory of 2005 when riots and car-burnings from the banlieues were repeated as far into the centre as the Marais district.