During the humidification of operating gases for a fuel cell, the operating gases cool to such an extent as a result of the loss of evaporation heat that they cannot absorb humidity to prevent damage to the membrane of the fuel cell. To solve this problem, a fuel cell assembly includes a humidification cell, which contains a planar heating element. The humidification cell is configured in terms of shape, location and materials in the same way as a fuel cell of the fuel-cell stack.