Although the ornamentation of the Lascaux cave seems relatively homogeneous in style, the analysis by scanning and transmission electron microscopy of 32 microsamples from the figures of the Hall of the Bulls (Bull Rotunda) and one desquamated sample from the soil highlighted different paint pots. The black and red paint matters with their associated mineralogical phases were extensively characterized. Considering previous stylistic and superimposition studies, we were eventually able to confirm five creation steps of monothematic figures (‘assemblages’) based on the chemical and mineralogical characteristics. Further interpretations in terms of the rhythm and temporal framework of the Hall of the Bulls (Bull Rotunda) of the Lascaux cave could be reinforced. Some particular representations such as the black cave bear and one of the cross‐shaped signs were shown to be likely added at later moments by different hands because their paint pots were different from those of the Bull Rotunda and similar to that of other representations in deeper rooms of the Lascaux cave. We also found that the paint matter of the Bull Rotunda was different than those of other Palaeolithic cave sites on a more regional scale indicating a very local sourcing.