The Festival de Cannes has announced the dates for the 65th Cannes Film Festival: 16 - 27 May 2012. It should be noted that this is around a week later than normal (we had originally expected it to run 9-20 May).
One of the main effects of these later dates will be that the last weekend of the festival will coincide with the Monaco Grand Prix. This is likely to put upward pressure on flight prices around that time as both events use Nice International Airport as their entry point. So unsurprisingly, we recommend booking flights early.