The film in question is Dudok de Wit's The Red Turtle, the debut feature from the director of Oscar winning short Father And Daughter. The story goes that Miyazaki was so taken by de Wit's short that he reached out to Studio Ghibli's international sales agents, The Wild Bunch, and asked them to track he man down and reach out on Ghibli's behalf. The result is a co-production between Ghibli, Wild Bunch, Why Not Productions, Belvision, Arte France Cinema and CN4 Productions with Paris-based Prima Linea overseeing the animation.
That image up above is the first released still from the picture with word being that Wild Bunch will be presenting the first footage in the Cannes Marche du Film.