How do memory systems cope with situations where a large amount of information has to be remembered? One solution is to separate the information into chunks to facilitate learning. We propose that in the hippocampus, sensory cues can parse spatial representations coded by hippocampal units thereby facilitating spatial learning.To test this hypothesis, mice were trained on a difficult spatial task in a large environment: they had to learn the positions of water rewards on a double cheeseboard maze, with two sets of rewards on two separate platforms. These rewards contained either no odour (NO-Odour condition), or odours specific to each set (TWO-Odour condition). After learning and a rest period, mice were tested for their ability to retrieve reward locations on the maze, without any odours in the rewards.Memory performance – both during learning and retrieval phases - was increased in the TWO-Odour compared to the NO-Odour condition, suggesting that the presence of odours during learning facilitated memory acquisition and its consolidation. Silicon probe recordings in the CA1 layer of the hippocampus revealed that cell assemblies detected from the TWO-Odour condition were more selective for individual platforms than those from the NO-Odour condition during the learning task. This effect was also observed within individual sessions, when odours were introduced on one of the two platforms only. Interestingly, selectivity correlated with reactivations during NREM-sleep. These data suggest that the presence of odours during learning leads to more distinct task-related neuronal assemblies that are more likely to be consolidated, potentially facilitating memorisation.