Comments about Ending (Spoilers)
This is a very ambitious and, apparently, at least semi-autobiographical film by Assayas.
The ending was strangely poetic. I assume that Laure is dead and that this was a short film she had appeared in. Gilles built that memorial by the tree which he notched each passing day on.
According to his imdB credits, Assayas himself never worked in England on a dinosaur flick, but he did work on stuff like 78's SUPERMAN and CROSSED SWORDS. Interesting.