The centre's 81st-minute try ensured Northampton are still in contention of topping Pool One ahead of their final group match against Magners League champions Munster at Thomond Park next weekend.
The German economy grew 0.3% on a seasonally adjusted basis in the second quarter, topping forecasts of a 0.2% rise, while France's economy stagnated in the quarter but still topped expectations of a 0.1% contraction.