The spectre of the Charlie Hebdo killings still hangs over Paris. Outside the École Nationale Supérieure des Beaux-Arts, opposite the Louvre, there’s a big poster of Cabu, one of the murdered cartoonists. The poster is peppered with fake bullet holes; underneath, the caption reads, ‘It doesn’t hurt at all.’

I didn’t realise, until I talked to the curator of the new Impressionist show at the National Gallery in London, that Cabu was a popular figure on French children’s TV in the 1970s.