The maybe most famous border marker between France and Monaco is in fact not a border marker, but a road stone.  It marks a point on the 7th route Paris - Nice - Italy. 

Towards northwest: 

Route N^le N^o 7 de Paris à Nice et en Italie. 

France Alpes MarIt^mes | Princ^te de Monaco.

Towards southwest: Nice and 18^K 6

Towards southeast: 

Route N^le N^o 7 de Paris à Nice et en Italie. 

Princ^te de Monaco  |  France Alpes MarIt^mes 

Towards northeast: 

Monaco and 2^K 2.

Distance to Nice: 18,600 metres.

Distance to Monaco (Ville): 2,200 metres.

Photograped across the Charles III Boulevard and towards northwest.  Compared with the tourist maps the stone appears to stand in a slightly incorrect angle. According to the maps the boundary runs further slightly east of the brown building.

This touristic welcoming stone is of a similar type as the Place Antoine-Repaire stone.  The coat of arms, texts and style are also the same as the Blvd. du Jardin-Exotique column.  This stone stands on the opposite side of the Monaco enter signs, about 10 metres north of the boundary, and about 16 metres north of the road stone.

Route no. 7 is in 2011 a highway route going from Paris via Nice to the French-Italian border. 

The 2011 Route no 7 is now following the green-marked road at road no D6007, and is on its closest 325 metres away from where the Bvld. Charles III road stone now stands (FRMC1). When the road stone was put there Route no 7 was clearly going through Blvd. Charles III and Monaco.

But further north Route no 7 passes through Monegasque territory – but only on its northern lane – where France and Monaco shares a 85,5 metres long boundary.

View from Monaco and southwest towards France. Note the road stone in the left part of the picture.

Entry traffic sign to Cap d'Ail in the region of Aples-Maritimes.