When I first got my Europa, I drove it with what I called "indoor track shoes." Now, tennis shoes are (universally?) wide in the sole and totally useless for driving a Europa. Speaking for myself, I have had no problem driving with dress loafers (that are pretty narrow) and moccasins, but for most occasions where I would drive my Europa, I would prefer to wear something casual and more appropriate than slippers. Here are two options I've found.
The first was these:
https://shophunziker.com/collections/casual-driving-shoes/products/british-racing-green-casual-driving-shoe?variant=30573215876. Actually, I had an earlier version with the number "5" on under the laces. The style of the shoe is an homage to Jim Clark's Lotus 49 when he won in its inaugural outing being powered by the Ford DFV also in its inaugural outing. It gets car geek points but I always felt I had to explain that they were not bowling shoes. They were comfortable and are true to size. My only complaint in that department was that the laces that came with them were much too long. I tried to get some shorter yellow laces but they ended up being a neon yellow! After several years, they started to come apart (I hadn't heard of Shoe Goo) and so they are now my backup shoes. Several months ago, they were on sale for $50 but now they are $125. I wonder if they are deeply discounted from time to time.
More recently, I found these Pumas (
https://production-pna-sfcc.puma.com/us/en/pd/redon-bungee-shoes/195551021144.html. These are my new driving shoes. The styling doesn't draw undo attention, they are narrow and they are pretty comfortable. Puma recommends that you buy 1/2 size larger than you would normally. I think that's good advise. I have always considered that I have a narrow foot and these feel narrow on me even with buying 1/2 size up. The bungee laces are nice because they obviously don't come untied but with respect to tightness, you take what you get. They are very flexible and the soles are very thin so it's an open question how long they will last. I would say they aren't quite as comfortable as the Hunzikers above but I can certainly wear them all day. And, of course, the price is right. I've only had them for a month or so so I don't have a long term review but I am wondering if maybe I should get another pair just in case. I'm a happy customer!