After what appeared absolutely fine for the first four minutes of our arrival with a friendly welcome, a bottle of wine out and croissants, this became one of the most distateful and infuriating experiences of the last few years of my life. On host Clara preparing to leave, she indicated she had made a mistake in an email (contracting that more of our party could stay, after the AirBNB contract had been agreed, for €50 extra for each of 2 extra mattresses on the floor for each of three nights - so €300, in addition to the full fee of over £1600 for the normal AirBNB rental). Despite having indicated this was her mistake Clara demanded a further €150 as it was now on the basis of the number of extra people staying rather than the number of mattresses, contrary to her email. She calculated three extra people x three nights x €50 a night. Clara refused to accept she was wrong to unilaterally reinterpret the contract based on her alleged "mistake" in the email wording and phoned up her mother Florence who I was also obliged to speak with as well within five minutes of arriving from our flight after several hours of travelling with my wife, three young children and 79-year-old mother who has diabetes. Despite six months between her email and our arrival the mistake was not mentioned until our arrival. As a lawyer I was astonished to be faced with a demand for the money. Our hosts were intransigent until it became apparent that the number staying was 12 and not 13 as someone they initially thought was coming could not; hence even on the brand-new and flawed basis of charging us €150 extra there was no basis for that. I paid over the previously agreed extra €300 after insisting on a receipt and received the receipt together with a clause that was not part of our initial contract. There was and still has been no apology. An uncle and aunt, who had arrived just before us asked were we actually able to stay as they were unsettled at what was happening, despite having reimbursed me their portion of the cost already. As I had organised accommodation for various members of my family you can perhaps understand the difficulty in approaching them for money that they had not been told about and that was not due. Matters were no better the next day when on a number of my other relatives (who were staying with a cousin who lives in Paris) arriving and then leaving all at the same time with us Florence was outside the property saying that she had been told they were 12 of us but she had just counted 17 us, thus requiring an explanation indicating 5 of our group were staying at my cousins! Other comments inapplicable in view of tainting of our holiday and lack of room to comment.