The European champions had already assured their passage to the last 16 but continued their winning streak at the expense of Belarus. Germany prevailed 31-25 after the teams had been level at the break.
A 100 percent record from four group games stands Germany in good stead as they look to top Group C and gain a better seeding for the knockout stages.
After beating Hungary, Chile and Saudi Arabia on Tuesday, Dagur Sigurdsson's side eased off slightly with qualification in the bag and unfancied Belarus were even 16-16 level at the break.
But eight goals from top scorer and captain Uwe Gensheimer and a man-of-the-match performance from Julius Kühn (5) helped the Germans seal the 31-25 victory in Rouen.
"In the first 30 minutes we did not graft enough and we weren't up for the fight," Sigurdsson said.
They face rivals Croatia on Friday in the group decider. Croatia, who beat Chile 37-22, also have a maximum eight points.
"Winning the group will be incredibly important for our self belief so we can continue riding this wave," the Germany coach added.
Germany were also given a boost on Wednesday by news that 2007 world champion Holger Glandorf would be joining the squad in time for the Croatia game as Sigurdsson looks to increase his options.