Whatever is coming from the unconscious to the conscious has already happened before, ie: this is the repeat. Going deeper into that, what is the pattern?
Is it personal to you, or is does it come from deeper in the soul or from collective evolution?
If it was a positive or especially alluring experience, a deja vu could be an expression of inner genius, alignment, or inner magician…
If the feelings in the dream were of suffering or a resistance quality, a deja vu could also be a new awareness of trauma pattern, charged projection or complex.
The deja vu could also be an experience of Divine Intervention ... a force from seemingly outside the realm, intervening in your dream world. This can also have relationship to your own experience of ‘genius’ - so the actions or what you were doing could connect to your inner Djinn.
Looking at archetype In Tarot, something like this would be expressed as a lightning strike as seen in The Tower card - causing the toppling of the tower and a complete new perspective.
Whatever the case, a deja vu in a dream is a noteworthy moment which deserves further drawing out. One could do this via amplification of the narrative, spaces, objects and feelings, to bring the archetypes closer into conscious relation and integration.
To work with a deja vu dream - make a shamanic journey or dream constellation and travel back into the dream to watch exactly what happens before and after the deja vu. Take note of the landscape, emotion and intentions of each character. During a divinatory dream journey one can also ask questions to the characters within the dream and see if they answer.