The cruise climb performance chart of the DA40-1.7TDI is a complicated one.
At 7000 feet, ISA conditions and MTOW, the climb rate is ~450 ft/min if I read the chart correctly. A 500 ft/min climb rate is achievable up to about 6000 feet, assuming MTOW and ISA conditions. At 8000 feet the ROC has already dropped to ~380 ft/min, and 10.000 feet gives you ~250 ft/min. According to the chart at least.
Subjectively speaking, the DA40 is not a very good climber. In order to get any meaningful climb rates you've got to fly the correct airspeed exactly (and there's actually three Vx's and Vy's listed in the handbook, each for a different TOW). In fact, we would typically climb to 1000 feet with flaps in T/O instead of UP. It might not give the best compromise between rate of climb and forward speed, but at least that way we got believable rate of climb numbers.