For years, Dominic Abels counted on Sunday business for a quarter of the weekly revenue his store earned in the now-posh Berlin neighborhood of Prenzlauer Berg. But in the past few months, the gaunt-faced Abels has been fined three times for keeping his shop open on Sundays in defiance of the law. The fine increased each time — from 400 euros ($440) the first time to 800 euros ($880) most recently.