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

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image-44831-kabloes starboardmark.gif?1448630150661
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 Lighthouses Nord Pas  De Calais                                                       
Lighthouses Poitou Charentes                                                           
    Lighthouses Aquitaine
     Lighthouse Bretagne
                                                                          click on the region to discover the lighthouses​ sorry not ready​

   Lighthouse Languedoc                  Roussillon

   Lighthouses Provence            Alpes Cote D'Azur
      Lighthouses Corse
 Lighthouses Pays De                       Loire
                                                                                Lighthouses Haute and  Basse Normandie