Tax for a side job?

Tax report that you just did was for the year 2019.
The tax report is always about the previous year (when the full period is over).
So you don't care right now, but next year

Did you had a contract? Do you have your own company / self-employee / vat / ...?
It also depends on the amount that you got paid... and on what terms/contract...

No contract, no terms, he is my friend so no need for that I thought.
I work full-time in a company, I don't have my own company.
The amount was 1500 euros.

Let's say it is gift money, is there tax for that? What index number?

I went though all the boxes, can't find a related thing.

Hello,

In reality, you have to be more subtle. Your friend gave you money for a job. But did he enter this amount on the accounts of his company or not? If it did and it undergoes a tax audit, the tax service will verify your declaration ... And if nothing is reported, you will receive a letter that will not make you happy at all ...