Besides the more than 700 numbered bordermarkers between France and Spain, there are many intermediate markers in all kinds of shape. The indefatigable Jacques Koleck once again found new intermediate bordermarkers in the Basque country and I’m impatiently awaiting his pictures. But thanks to him I can already show you these old postcards, found on the internet. They show the international bridge between Hendaye and Irún.
First an overview on this postcard:

What you hardly can see, are the two posts in the middle of the bridge.

But this postcard shows them very clear. They must be the two posts with both arms of Spain and France which are mentioned in article 26 of the Bayonne treaty of 1856. As such they are the very first bordermarkers mentioned in the treaty!
Jacques adds: “they have disappeared on the renewed bridge (which however has plaques with the ancient province-names) but similar posts can now be seen on the pedestrian bridge next to it.”