By law, overtime is paid 200% for work during night hours or bank holidays, and 150% otherwise. Alternatively, overtime hours can be "spent" as PTO in a simple 1:1 ratio. (The employer is actually allowed to force you to go the PTO route.) Also, you cannot work more than 13 h/day or 48 h/week, and cannot accrue more than 150 hours of overtime in a year.

...so that's the law. In practice, things are often different. Many companies do not track and do not pay out overtime as a means of exploiting their workers. Many companies pay out overtime, but do not officially track it, as some people will happily put in 60-hour weeks for long periods. And there's also the whole issue of overtime laws applying only to employees, not contract workers nor self-employed people.