I did not get any paper that I have to bring in to pay fine like what I’ve heard my friend had to before.

Well, you did pay, so there would be no need for that.

2) Will I be in any trouble?

Doesn't appear like it, however i don't understand the anonymous part of it.

I don’t know how serious an offense getting caught like this is.

Technically a misdeanor, but the €60 is a contract penalty. If you get caught too often the company will report you to the authorities and there will be increasing fines. (And technically possibly jail time for the absolutely worst repeat offenders.)

Honestly, if you didn't get a receipt, i figure the person checking you pocketed the €60 for themselves and didn't even enter your details in the system anywhere. Which technically is stealing from the company, but what are you gonna do.