The Rafale jet deal negotiated by the BJP-led government in 2015 was a windfall for French aircraft-maker Dassault, Congress leader P Chidambaram said today, citing an investigative piece by the Hindu newspaper that said Prime Minister Narendra Modi's decision to buy 36 fighter jets instead of 126 - negotiated by the Congress-led government - raised the price of each aircraft by over 41 per cent.