It is not French amber ,though French amber flints found their way here.
In time a quarry site may be found with a similar type flint.
Here is some ideas.
You might start by locating nearest quarry sites to where you found your sample.
Though worked material did travel at times!
Any chance it could've been brought here? I also found these shells in the same layer. The first one on the left is a saltwater shell so it makes me think?