I have just re-checked the article in the Athens News that gave the information about Residence Permits no longer being required and it says:
To register, EU citizens are required to submit the following documents:
- a valid identity card or passport; and
- confirmation of engagement from the applicant's employer or a certificate of employment or proof that they are self-employed.
Those who are not active in the labour market will only need to submit proof of medical insurance and that they have sufficient monetary resources for themselves and their family.
The registration certificate should be issued on the spot. It is also free of charge.
The article doesn't make any mention of having to have tax certificates but, thinking about it, I wonder whether applicants might be asked for these as "proof that they are self-employed"?
I guess we will have to wait until a few more people have been through the process before we can get a good idea of exactly what is required in every scenario.