I call BS!!!
The "Code Civil" did not even come into being until long AFTER the constitution was ratified. Indeed - the "Revolution" in France did not even begin until 1789! French "democracy" thus post dates the US Constitution.
You are confused. That continental law was developed after US constitution does not mean that the underlying ideas did not develop in Europe or France. It is common that ideas are implemented faster in the periphery of the civilization.
And the point is with the Constitution that it is the main element in US law that resembles the logical structure of the codex. And most of Americans think that US Constitution is the greatest thing in their law, for a good reason!
French "democracy" thus post dates the US Constitution.
Hey, French had monarchy well into the XIX century, so what? And the Fifth Republic is quite new.