And be even more careful to sell this amount.
Its funny how every day newbies appear here who wanna buy/sell BTC Millions or Bilions worth...
On the other side there is a majority of scam-attempts in this section of the forum...
...and there are groups of scammers, specialised for bigscale cash-scams.
https://bitcointalk.org/index.php?topic=5154558.0Thats no joke, theese guys are trying nonstop since years to activate middlemen like you.
There are established OTC-Desks operating.
But no serious buyer/seller will do that via this forum.
There is no reliable escrow for this amounts available in this forum.
Without real/established/trusted escrow dont even think about trading that amounts with strangers.
If you are not experienced in P2P trading, let it be. Dont start will millions of Euro, start learning with dozends of Euros.
Otherwise you will get trouble.
Dont want to say OP is a scammer.
Just say, take care.
By the way,
https://bitcointalk.org/index.php?board=53.0 is the right place to publish that kind of offers in bitcointalk