End of lease – staying put pending sale of property

Dear all

Our 3year lease ran out in August. Shortly before, the owner, Sylvie, had agreed to sell the property and introduced us to Monsieur ABC. the incoming owner (whom we think may be a family friend).
We want to stay put, so had a brief chat with ABC and verbally agreed a new (increased) rent.
We haven’t signed a new lease with Sylvie, and obviously not with ABC until the sale goes through.
But for reasons we don’t know, the sale has been delayed.
In the meantime we are continuing to pay Sylvie (by cheque) the rent which applied in the last 12 months of the original lease.
However ABC phoned the other day saying that he we should already be paying the increased figure.
Not sure why he is involved since he doesn’t yet own it.
But in any event, what’s the legal position?
TIA

Talk to a notaire. While on the one hand you might legitimately refuse the rent increase, on the other you are in the only situation (I think) where your lease can be unilaterally terminated by your landlord.
So go and see a notaire!