The Reds will take on 13-time winners Real Madrid at the Stade de France, just north of the city, on Saturday, and supporters have been flocking to the French capital since Thursday morning.
However police have warned that wearing any football club colours is banned near the Champs Elysees until after the final.
It covers the popular tourist attraction area from the Place de la Concorde to the Arc de Triomphe.
Merseyside Police Liverpool FC said on Twitter: “As of 15.00 on 26.05 until 18.00 on Sunday 29.05 it is prohibited to wear any football club colours in the area of the Champs Elysees.
“This includes scarves, hats, displaying banners etc. The police can issue a 135 Euro fine.”
It comes as Liverpool fans with banners, flags and flares could be seen at landmarks across the city.
Up to 70,000 fans are expected to arrive, according to local authorities, with some leaving early in the morning and driving for 10 hours.
Crowds were seen close to the Eiffel Tower on Friday afternoon, where banners have been displayed, while Scouse accents can be heard in bars around Gare du Nord.
Lines of police vans and armed officers can be seen patrolling the area close to the train station.
Steve Ryans, 33, a fan who travelled via train on Friday morning from Kingston, south-west London, told the PA news agency: “No ticket but I don’t care.
“I had to see Liverpool win the Champions League in person, I missed the last few.
“There’s so many Reds here, everyone’s having a laugh. It was worth the journey.”
Another supporter named James Macey, 24, from Birkenhead, said: “I left around 4am yesterday, I’m not looking forward to leaving here but I had to be here with the lads.
“I don’t even have a ticket but we’re not here for the stadium, it’s just to be with fellow Reds, it’s gonna be boss.
“Hopefully they can win to cap it all off.”
Gary Stone, 47, a landscaper from Woolton, said: “It was a real mammoth journey, 10 hours, no sleep but what a laugh it’s gonna be.
“It’ll be a carnival atmosphere – no-one does it like the Reds, we’re the best fans.”
Three supporters from Cheshire said that most fans they had spoken to did not have tickets for the match.
Banners seen around the city read “Up the Reds”, “There are some things oil can’t buy” and “Conquering Europe”.
However, there were a few reports of people going missing on Thursday evening.
Fan James Hargreaves, 31, issued a plea on social media saying his 66-year-old father was missing after drinking at a Liverpool-themed bar, but he was found hours later.
Another fan said on Twitter his friend had disappeared without a phone.
A fan zone will be set up in the south-east on Cours de Vincennes, more than 10km away from the stadium.
Prefecture de Police, the Parisian police force, said 6,800 officers and military personnel will be “mobilised”, with flares prohibited from the fan zone.
It said up to 44,000 supporters will be permitted in the area, which will remain open until the end of the match.
The zone will open from 2pm local time with fans able to access it for free.