EDIT: Apparently from https://etherscan.io/address/0x6a164122d5cf7c840D26e829b46dC... , which is something I don't have the depth of knowledge to assess for myself.
is the important figure. At the bottom you can see the transactions coming in.
First incoming transaction seems to be from Jul-17-2017 01:01:21 PM. View all > last page.
Who knows what the price will be next week, but it won't be anywhere near €6,000,000 if they try to sell that much at once.
A number of large transactions to convert that much ETH to USD, would significantly affect speculator confidence, triggering others to sell.