Just came back to say, the max I can buy (Ivories are subject to an annual limit, which does not apply to Elites) is 75,000 miles + 37,500 bonus miles = 112,500 Award Miles for €2062.50.

The minimum you need for a business class return from CDG to the US is 125,000 miles (or as much as 375,000 miles when charged at the Flex rate).

So, my €2062.50 spend would not even pay for a return business class flight.

(Remember also that you will have to pay fees and charges when you redeem your flight - and to travel on direct AF services between CDG and JFK in business class, the fees currently come to €506.53 - so don't forget to factor in this charge, too. If you are willing to take indirect routings via AMS in both directions, the cash element on a mileage booking can be reduced to €474. You must therefore factor in that you will be have to spend around an additional €500 per return J flight on top of whatever you spend to buy the miles. On the CDG-JFK-CDG route in economy, these additional fees/charges start from about €200).

Now, having searched for a business class ticket from Paris to New York departing tomorrow and returning Sunday - so, a last minute ticket which shouldn't come cheap - I could fly with La Compagnie for €1658.40. (They have lie-flat seats to the best of my knowledge on this all-business class airline)

If you can plan a bit in advance, you can travel in business class for less than €1500 on La Compagnie or Icelandair (no experience of either, but clearly La Compagnie, being direct and lie-flat is the way to go; not sure that Icelandair has a "proper" business class); for about €1700 on Aer Lingus (short haul, single-cabin plane to Dublin, but you clear US immigration and customs there, and travel on a newly refurbished business cabin with all lie-flat seats); for about €1900 on Alitalia (their Magnifica class is probably the best business class offered by any European airline - additionally, you can earn Flying Blue miles on this itinerary), LOT or TAP, and for prices just above €2000 on a range of carriers (including Air France/KLM/Delta, Air Canada, Air Europa, Austrian, British Airways (including Openskies direct on ORY-JFK), Brussels Airlines, Finnair, Iberia, Lufthansa, Swiss, etc. (All prices given for travel in August 2016).

As such, my spend of €2062.50 would be better off buying a revenue ticket (for which I would additionally earn some miles) rather than going towards a stock of 112,500 Flying Blue miles which will not get me to the US, and would still require me to cough up an extra €500 anyway.