Before people get to into the release clause thing.
If we have to make a payment, we will do it on the player's behalf - there's now case law to back up this direct payment method, so there's no income tax.
A 36m Euro clause written in 2011, may contain an inflation factor (like Illaramendi's) however given they are talking about it going up to 40m next year, I'd guess we're being quoted the current total.
If you pay a release clause, you may have to pay the IVA (VAT) as you would on a normal transfer so that adds about 7m. However a VAT registered entity gets its VAT back so that's no big deal. Indeed as a foreign EU company we probably won't actually need to lodge the IVA as international payments are done without it.