Concealing an identity in early 19th century France?

Question

So. How easy/hard would it be to conceal your identity if you were living in, say... Paris in the early/mid 1800's? What papers were needed to prove your identity, and how would you prove it if you were traveling, or something of the sort?

Answer 1

The papers were so easy to forge that everyone was able to cheat.  Or disappear. France was not very restrictive about crossing over provincial borders. Your name was written in a book of births at a church. That was it.  No drivers licenses, etc. /