A French law has forced the fast-food giant to serve fries and sodas in washable containers; now it is fighting a wider rollout PARIS—A McDonald’s MCD -0.44%decrease; red down pointing triangle on a buzzy boulevard here offers a glimpse of what the future of serving fast food could look like. The burger giant doesn’t like what it sees. For those dining in, french fries are served in durable red containers, soda is dispensed into clear washable glasses and chicken nuggets come in hard plastic white bowls. When customers are finished eating, they are asked to drop the containers into a...