The young French journalist at the next café table was moaning disconsolately into his iPhone. ‘C’est idiot! C’est superficiel! I came here for serious cinema – but there’s nothing here but le showbusiness!’ It was his first visit to the Cannes Film Festival, and two days in, he was shocked at the preponderance of glitter. I don’t normally make a big thing of playing the seasoned old hand on the Croisette – although this year was my 21st visit to the festival – but I couldn’t help leaning over and reassuring him that there was plenty of seriousness to be found in Cannes, despite the opening days’ obsession with glamour. In fact, there could hardly have been a more misleading opening film than Baz Luhrmann’s bling-laden 3D version of The Great Gatsby.