Suppose you win 100 million. What do you actually do with it? Banks only guarantee 250,000. Do you have to invest it? Is there anywhere you can just let it sit and draw interest?
Here in Norway you are legally required to attend a few sessions with financial advisors(a protected title here, so they will actually be qualified), before you are able to recieve your winnings.
The rough thoughts I have had about being in such a situation is to allocate maybe 10%-20% as "fuck you money" to have fun with, and the rest to follow all their advice with
France does that too. It's not a legal obligation, just something the local lottery does, presumably to avoid bad publicity of winners going on a tasteless spending rampage.