At the firm he renamed Rheingans Digital Enabler, the 16 employees start work at 8 a.m. and may leave at 1 p.m. Mr. Rheingans, the firm’s managing director, says employees can deliver the same output during a focused 25-hour week as in 40 hours interrupted with distractions.

“We have all experienced that: We sit in the office, out of energy, reading newspapers online or Facebook, just in need of the little pauses to recharge, but you don’t really recharge,” he says. “My idea is focusing on the first five hours and then just leave, and have a proper break.”

To accomplish that, small talk during work hours is discouraged. Social media is banned. Phones are kept in backpacks. Company email accounts are checked just twice a day. Most meetings are scheduled to last no more than 15 minutes.

As a result, the company produces the same level of output for clients despite shorter days, says Mr. Rheingans. He says the company, which develops websites, apps and e-commerce platforms, was profitable in 2018, the first full year he owned it. He says happier employees deliver better work for clients, and the shorter workday is a draw, boosting recruitment in Germany’s tight labor market.