Traveling to Pokémon GO Fest Paris on June 13 - 15 without the ticket?

My girlfriend and I had a really tough time in the last weeks. We really wanted to travel to Paris to the Pokémon GO Fest on June 13 - 15 but due to our mentioned hassle we forgot to buy the tickets in time and now they're sold out.

I was able to find out that the ticket only would've been valid for a specific time (four hours) on one single day. I guess without the ticket you only can't access the Parc de Sceaux but I don't know because Naintics descriptions aren't that clear imo.

That leads me to the question if the ticket really is necessary to enjoy playing Pokémon GO in Paris on June 13 - 15 and getting special Pokémon, backgrounds etc.

I never visited a Niantic Live Event and I really don't know what differs the regional Pokémon GO Fests from the global one. So maybe someone can give us clarity here.

We would travel 750 km so it would be needless if Paris 13 - 15 wouldn't make a difference to the global fest on June 28 - 29 for us because of the missing ticket.