In the context of Brexit, there has been much discussion that the border between Ireland and Northern Ireland would mark the boundary of the EU. This has had large ramifications due to the length and porous nature of this border, and the large amount of interconnections between the economies of Ireland and Northern Ireland.

There is currently a question exploring the nature of that hypothetical border, but I'm not interested in that here. Specifically, what I want to know is whether French Guiana, a part of France and member of the EU, has a similar 'hard' border.

As is evident in the attached map, French Guiana is very isolated from the rest of the EU, and possesses a very long border with non-EU nations. It is also a border that is (presumably) virtually impossible to police, as most of it falls within the Amazon rainforest. While it isn't a member of the Mercosur trade block, French Guiana presumably is very reliant on trade with its neighbours.

So, as the border of the EU, does French Guiana have an open and free-flowing border with its neighbours? Or are there border posts and heavily restricted movement?