I think it's impossible to say what a "fair fine" would be based on the evidence provided in the thread.
"He got fined for flying higher than 400ft, far away BVLOS, and over a city." OK, so that's a breach of the rules on three separate counts (that we know of). On it's own, that's probably a pretty steep cautionary fine, but still way less than the maximum limit of €220,000 - maybe in the hundreds or thousands of Euros depending what's typical for Spain and taking into account the exact nature of the flight, and given no actual harm appears to have been caused?
But then there's "several times without permit or insurance", so that's going to ratchet things up a bit. If he's been continuing to make these flights after being fined for earlier ones, then I'd expect that's going to be a fairly large uplift, if the pattern of behaviour only came to light after a single investigation, then maybe not so much, but potentially still a big chunk of change.
This is clearly someone who doesn't care for the rules or the safety of others, and I expect the judge is going to take that into account when deterimining what is a fair penalty for the infringement. Personally, I've got little sympathy for behaviour like this given it makes things a lot harder for the rest of us, so think a pretty steep fine is in order even if this is the first time he's been prosecuted. If he's been continuing to offend after earlier cautions or prosecutions, then the penalty should be increased accordingly, but even so I don't think it's going to come close to the €220,000 limit based on what we know so far.
Of course, the judge might just see this as a good opportunity to set an example to discourage others, in which case all bets are off.