In practice, you have to have half an hour 'off the clock', but the EU doesn't know or care whether you're actually getting a break in that time. If you need to work through your lunch break you'll be expected by your employer to work through your lunch break, but you can't count it towards your required hours, and if you're paid by the hour or get paid for overtime it'll be unpaid.
If your employer expects you to work through your lunch break, then they are - with very high probability - involved in illegal shenanigans.
Even if there is no explicit law that states an employer is required to give an employee a half hour break, as an employee you are usually still legally required to take a break. In that event your employer cannot force you to continue working, because they cannot force an employee to perform an illegal act on their behalf.
Usually though, there are additional provisions in law that make it legally required for an employer to force an employee to have a timely break.