Dejavu is a phenomenon of feeling as if one had lived before through the present situation which appears to be happening again.
It's possible you've seen a scene that appears to have happened before with exact details. You try to recall at what time you've seen it but most often don't have clear knowledge. Believers of reincarnation believe it's an event you've come across in your other life(the life you've lived before) and is the reason why one keeps seeing familiar events and faces. They believe those who have died do come back to live again and we are probably one of the people from before and can only get in touch with our previous life through Dejavu and the physical aspect being the resemblance of who we reincarnated.
I don't believe in reincarnation and resemblance can come from genes and other factors outside of genes. Our fathers of old called a child who comes in exact resemblance “ogbanje”, they believed the person who died was coming back to life, until civilization set in and they realized the role of genetics in child bearing.
If I don't believe in Deja Vu as a reincarnation fact, what then brings such feelings of a scene replaying itself?.
I may not have the exact answer, but two things play a role in Dejavu; dreams and imagination. If Dejavu happens because we've lived before, then it's expected that we see scenes we've encountered before on a regular basis and that's because we probably lived many years before our death. Dejavu happens only once in a long while, which may probably be a scene from one of our imaginations or something we've dreamt about but forgot before dusk.
Lastly, my faith has no record or documentary on reincarnation. If many people live as me through the years, then who exactly would be judged on the last day? Will all my reincarnated personality appear and be judged differently? If no one has any record of his past, then it probably wasn't him. A child can look like someone who had lived before, act like him, and probably carry a birthmark that looks like him, but it's all genetics and other factors like , what the woman had seen more often or thought about replicating in the embryo she carried.