That's the number of my official signature on the books at the Baladiyya-Chellah in south-western downtown Tangier (municipal services office). I assume the numbering begins anew each month.
My landlady had already registered her signature on the rental contract, but I had to as well (with another 2 dirham tax stamp, three more official rubber stamps and one more official's initials). I then took the contract to the copy shop and got two copies. Then I went back and stood in line for the photocopy to be legalized, which meant it got four more rubber stamps and another official's initials. (I had already had the copies of my other other official documents legalized early that morning.)
Then I took my entire packet over to immigration to submit for my residency application.