Despise the fact the French will arrive as massive favourites for the Six Nations clash, the France coach has claimed the relentless singing in Cardiff “levels the playing field”.
The defending champions will come to Cardiff after an emphatic 36-14 victory over Ireland, while Wales are attempting to regroup following a 48-7 hammering by England at Twickenham.
There were also thousands of unsold tickets still available, with 15,000 remaining on Thursday afternoon.
On paper, it looks a horrible mis-match, yet Galthié has warned that the setting — and the emotion it generates — can transform the contest.
"For me (it is) the most beautiful stadium in the world, with those Welsh chants that never stop," he said.
"It's special and, in my opinion, it levels the playing field. It gives the Welsh an extra spark."
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That acknowledgement underlines the respect France are affording opponents who are in danger of a record-extending 13th successive Six Nations defeat.
Despite Wales’ desperate struggles, Galthié is aware of how different a challenge Cardiff on a Sunday presents compared to a Thursday night in Paris.
France will step into that atmosphere with a new midfield pairing, as 20-year-old Fabien Brau-Boirie is handed his Test debut at inside centre.
The Pau youngster replaces Yoram Moefana, who suffered a knee injury in the win over Ireland.
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Moefana’s Bordeaux-Bègles team-mate Nicolas Depoortère is also sidelined with a calf problem, while Kalvin Gourgues (ankle) is unavailable after being hurt late on in Paris.
Brau-Boirie will link up with his Pau colleague Émilien Gailleton in the centres, a partnership that has helped propel their club into second place in the Top 14.
Gailleton earns his 12th cap, while Brau-Boirie takes his first step onto the Test stage in one of rugby’s most charged arenas.
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Galthié has been monitoring the young centre’s progress for some time.
"Brau-Boirie has been with us for over a year. He performed well with the under-20s, trained with the French national team last year, and was also supposed to travel with us to New Zealand (last July) but injured his ankle," Galthié said.
"He's a very young player but he's a regular for his club every weekend and has earned a place."
The selection is one of two changes to the starting XV, enforced largely by injury.
On the bench, France have opted for a 6-2 split, with Noah Nene the only outside back among the replacements.
The 21-year-old Stade Français centre is poised to make his debut from the bench, stepping in for Gourgues.
Wales name their team on Friday morning and are preparing to reshuffle their midfield and loose-forward combination.
Head coach Steve Tandy is not expected to overhaul his starting XV.
Scarlets playmaker Joe Hawkins is pushing to come in at inside centre, potentially displacing Ben Thomas in the No 12 jersey.
In the pack, Leicester’s powerful forward Olly Cracknell is set to add greater ballast to the back row as Wales look to inject more physicality into their forward effort.
There could also be alterations in the front row.
Nicky Smith and Archie Griffin were handed starting roles at loose-head and tight-head respectively at Twickenham, with Rhys Carre and Tomas Francis providing impact from the bench.
A switch in the prop department is under consideration as Wales seek a stronger platform at the set piece.
Beyond those tweaks, Tandy appears inclined to keep faith with the bulk of the side as they attempt to respond against the reigning champions.
Wales face a quick turnaround after Sunday’s encounter, with Scotland due in Cardiff on 21 February, leaving limited time for major reinvention.
France: Ramos; Attissogbe, Gailleton, Brau-Boirie, Bielle-Biarrey; Jalibert, Dupont (capt); Gros, Marchand, Aldegheri, Ollivon, Guillard, Cros, Jegou, Jelonch.
Replacements: Lamothe, Neti, Montagne, Flament, Meafou, Nouchi, Serin, Nene.
