[GuB-42]

Having a display in the sound booth is mandatory in France. Because the sound booth is usually in the middle of the stage, it is usually visible to the public too.

The maximum level is 102dB over 15 minutes. When I look at the screen in a loud venue (EDM, rock concert, ...), it is usually around 100dB, which more than justifies earplugs.

Free foam earplugs are common too, and they also sell better sounding earplugs in larger events. Personally, I bought custom molded earplugs, the type used by musicians. Expensive (~$200) but in my case 100% worth it: the others I tried tend to fall off, seal poorly, or be uncomfortable, and in the case of the cheapest ones (like the ones you get for free), completely muddle the sound.

[dolmen]

Any purchase advice? I'm in France too.

[pavon]

I'm from the US, but have been very happy with etymotic brand earplugs. They have inexpensive ($15 USD) standard designs as well as custom-fit. Either sound much better than foam plugs.

[GuB-42]

I have the Interson Protac Pianissimo, with 25dB filters, I had them made at my local audiologist (Amplifon) a few years ago.

I am very satisfied, and I never suffered any kind of hearing loss or tinnitus after wearing these and while not perfectly linear, I could fully enjoy the music. If anything 25dB is a bit too much for "reasonably" loud events and I am tempted to buy extra filters with less attenuation for these events.