Yes, they're all around the €20 mark but they definitely do come with sides....you won't be hungry that's for sure. (Actually it says at the top that all burgers come with two sides.)
There's a restaurant we were very regular diners at, which bumped up the price to that sort of price just over a year ago, and it rankled a bit with me, but what stopped me going there since was them reducing the portion size at the same time. I can accept the price increase but adding the portion reduction was a step too far.