The color red and green to indicate port and starboard. Port = left = red / green = Starboard = right.
On the Schelde and other large streams, the channel also marked with red and green buoys.
On a ship or aircraft fire along the port side a red light and a green light and starboard.
If you are on a ship and looks in the direction of travel is portside left and starboard right.
Especially in France one finds small lighthouse side of the harbor entrance with a red and light green painted house
click on the region to discover the lighthouses sorry not ready
Lighthouses Haute and Basse Normandie