What is a GR route? French footpath signs (hiking trails) explained
It took me years to understand the logic of French footpath signs, finally resolved by attending a weekend course for baliseurs, the volunteers who actually paint the signs. You can read more about this fascinating experience in The Nature of the French. The most revealing thing I learned was that the signs are meant to be discreet. Practical usefulness is all very well, I was told, but aestheticism is more important. Not all French walkers agree. A helpful French website explaining how not to get lost when following the signs is http://www.randonner-malin.com/le-balisage-en-randonnee-ce-que-vous-devez-savoir/
The footpath signs were created by the FFRP (Féderation Française de la Randonnée Pedestre, https://www.ffrandonnee.fr/), the equivalent of the Ramblers’ Association in the UK or the American Hiking Society in the US. Their volunteers are responsible for maintaining the system of letters and coloured markings which help you find your way across country. These waymarked footpaths are shown in red on the IGN (Institut Géographique National) large-scale maps.
On the ground the red and white or yellow markings are deliberately rather discreet, usually painted at eye level on a tree or lamp-post. However, once you start looking for them you will notice them everywhere, including central Paris. It is generally a good idea to follow the FFRP paths, which avoid busy roads as far as possible, sometimes leading to an unsuspected underpass or taking you through a pretty wood.
Footpaths are classified as follows:
GR (Grande Randonnée): Major footpath crossing several regions. Red and white stripe.
GRP (Grande Randonnée de Pays): Major footpath circling an entire region. Red and yellow stripe.
PR (Promenade et Randonnée): Shorter circular routes taking one to eight hours. Yellow stripe.
Two horizontal stripes mean you are on the right path, a horizontal stripe above a right or left angle means turn right or left at the next fork and a horizontal cross means you will stray off the path if you take this route. More unusually, two horizontal stripes with a vertical line through them indicate that the path is a diverticule, a waymarked deviation from the main one.