A Consultant anywhere in Europe, has to get registered as an Independent Entrepreneur.
If his/her annual turnover does not exceed 22,000 EUR, s/he can take advantage of the small business regulation system.
S/he is not subject to pay VAT to the tax authorities.
This means that s/he is also exempt from filing an advance turnover tax return. Also, simple accounting and profit determination are usually sufficient.
When registering with the tax authorities, s/he has to indicate in the "questionnaire for tax registration" that s/he wants to benefit from the small business regulations.
The status depends on an individual's unique situation. I recommend to check all needed information locally.