Both teams go into the contest knowing only a win will do as they fight for an automatic berth in the last eight of the competition. Pool 2 is finely poised with 2013 champions Toulon top with 15 points, closely followed by the Blues on 13.
The Blues will be buoyed by their home win against the French outfit in round 2, but Paulo is expecting another stern test in Nice.
"We managed a victory against them at home so they are not a team to take lightly and they will come out all guns blazing. They have a world-class team who will give any international team a hard game," said Paulo
Paulo and Williams played together at Auckland Blues before taking different journeys to Europe. The Kiwi linked up with the Cardiff Blues last season while ex All Blacks lock Williams joined Toulon towards the end of last year.
"Ali is a real character around the squad," said Paulo. "But he is also is really experienced and I learned a lot of little things off him.
"He has a big work ethic off the field and spends a lot of time looking at opposition lineouts before the game. He has a lot of time for the young guys and that made it easy coming through."
The duo have already faced each other when the Blues defeated Toulon 19-15 at the Arms Park last October when Williams packed down with South African enforcer Bakkies Botha.
"It is a good challenge playing when they are together and it's a real buzz to be up against the pair together," added Paulo.
The Samoan international is hoping the Blues can emulate their home victory when they travel to face the Heineken Cup defending champions today.
"We wanted it more on that day and we wanted it for the fans. We won the match through our defence and it was the best moment of my career."