Granted, when all the world knows you've won a big sum (in this case: 168 million Euro), you won't have a quiet moment left. Just everyone will be begging for money. The man who won this big amount two weeks ago didn't dare stay in Schaarbeek, where he lived and worked. He fled to Germany, to live with family there.
He had bought his ticket in a shop, of course. The system works like this: when you go to the shop to have your ticket validated, the screen will go black and you'll be asked to call the Lottery in Brussels. There someone will tell you you're the winner of a big amount. They will also ask you what you want to have known in the media. And this is where most people go wrong. They allow the lottery to share their gender, their age, their family situation, even their address. And the owner of the shop where the winning tickets was sold, of course also knows he had a winner. No wonder all the world knows who and what after a couple of days.
When you want to live anonymously (and I think it can be done) you have to play online. For starters, there will not be a single clue of to where the winning ticket was sold. And you go to the Lottery headquarters with your own contract. Have them sign nothing of your identity, gender, occupation, family situtian and address will be shared in the media. Just have them announce there was a winner in Belgium. The country is big enough.
And then, continue you ordinary life for some time. It's easier when you are alreay a bit older. In our case, my sister could go on working for one or two years, and then claim to have taken up some sort of leave (which does exist in the department of education). Then sell the house (we want to to this anyway, all the neighorhood knows) and move to the coast. Nobody there will know how much money you have in the bank. I don't think we would spend too much of all this money. Just freshen up the flat at the coast and do some more travelling. And stay in first class hotels and fly business class. There would be a lot left when we'd go - good for the charities we've been supporting for many years. The state would get nothing.