This is a chart on how popular the 500 euro bill is. Not so popular it seems (green line).
However, when we look at how much money we are talking about, we see that it is the second largest quantity of money in the system. See below. We're talking about 500 euro x 600 million = 300 billion euros.
300 billion euro is not a small amount of money if you compare it to the 2 trillion ECB balance sheet. It's almost 20%. So if everyone moves out of the 500 euro bill, what do you think they will do with it? Exchange it for smaller bills? Put it in the bank for negative interests? No, they will buy other currencies like the Swiss franc or buy foreign stocks or buy gold and silver. This will put pressure on the euro and push up gold.
If everyone with 500 euro bills would buy gold, it would mean we would see a demand of 7000 tonnes, which is twice the yearly demand for gold. You can guess what will happen to gold right?