Container wall for a container covered by a film

Container wall preferably made of concrete, in particular for containers for the storage and the fermentation of fermenting agents, which in the vicinity of the upper edge has an outwardly open clamping channel with an undercut for clampingly receiving an edge of at least one film made of plastics material covering the container on the upper face, the clamping channel having a narrow, outwardly open entry slot, the height thereof being smaller than the height of an elongate insertion profile insertable into the clamping channel, around which the film may be wound, the cross-sectional dimensions of the clamping channel, the entry slot and the insertion profile being such that the insertion profile in position relative to the entry slot is insertable via said entry slot into the clamping channel and is retained against being moved out of the clamping channel when the film wound around the insertion profile is under tension, characterised in that the narrow entry slot is only defined by an upper projection, whilst the approximately planar lower wall of the clamping channel merges without projections with the entry slot.