How do I extend my 30-day visa exemption in Chiang Mai, and do I need a TM30?

I have been to CM immigration recently and the TM30 is required for sure . They are very strict about it.

I’m also French and entered on visa exemption, I did 30 days extension last week in Bangkok and I didn’t need the TM30. There was even a sign in the immigration office saying that it is not required anymore.

Q. I would like to know which of the two offices can I go to carry out this procedure?

-> You can apply for a tourism extension at either office.

Q. What documents do I need to bring?

-> Attached is the general information on tourism extension. AFAIK, the Chiang Mai office doesn't require more documents than listed.

Q. Also, the owner of my Airbnb accommodation told me that I don't need the TM30 and that I simply need to provide my temporary residence address during the application. Is it correct?

-> If I remember right, and if there was no recent change, CM is rather strict about TM30. You need to have a TM30 receipt (or at least TM30 registration on the system). You can try applying for an extension using a contract with your accommodation first if you want. They don't accept your application if your documents are not enough. You don't have to pay the fee in that case, just spend your time.