Question: What is the seating capacity of the stadium at which the final of the 2009–10 Heineken Cup pool stage was held?

Context articles: 2007–08 Heineken Cup pool stage
2010–11 Heineken Cup pool stage
2013–14 Heineken Cup pool stage
1997–98 Heineken Cup pool stage
Stade de France
2009–10 Heineken Cup pool stage
2011–12 Heineken Cup pool stage
2011–12 European Challenge Cup
2014–15 European Rugby Champions Cup pool stage
2012–13 Heineken Cup pool stage

The pool stage of the 2007–08 Heineken Cup began on 9 November 2007, and was completed on 20 January 2008.
 Involved in the pool stage were the 23 clubs that qualified through their respective domestic leagues, and one that qualified via the Italo-Celtic play-off match in May 2007.
 The 24 teams were divided into six pools of four teams each, with each team to play each of the others in their pool once at home and once away.
 At the end of the pool stage, the winners of each pool advanced to the quarter-finals, along with the two best runners-up.
 The teams were then seeded, first by pool position, and then by points attained, in order to determine which teams received home advantage for the quarter-finals.
The 2010–11 Heineken Cup pool stage was the first stage of the current season of the Heineken Cup, Europe's top competition for rugby union clubs.
 It involved 24 teams competing for eight quarter-final berths; the quarter-finalists will then participate in a knockout tournament that will ultimately end with the final on 21 May 2011 at Millennium Stadium in Cardiff.
The 2013–14 Heineken Cup pool stage is the first stage of the 19th season of the Heineken Cup, Europe's top competition for rugby union clubs.
 It involves 24 teams competing for eight quarter-final berths, awarded to the winners of each of six pools plus the two top-ranked second-place teams.
 The next three best runners-up will be parachuted into the Amlin Challenge Cup.
The 1997–98 Heineken Cup pool stage took place in September and October 1997.
 The winner of each pool advanced to the quarter-finals, with the runners-up and best third placed team entering the quarter-final play offs for the final three quarter final places.
The Stade de France (] ) is the national stadium of France, located just north of Paris in the commune of Saint-Denis.
 Its seating capacity of 81,338 makes it the sixth-largest stadium in Europe.
 The stadium is used by the France national football team and French rugby union team for international competition.
 Originally built for the 1998 FIFA World Cup, the stadium's name was recommended by Michel Platini, head of the organising committee.
 On 12 July 1998, France defeated Brazil 3–0 in the 1998 FIFA World Cup Final contested at the stadium.
 It will host the opening and closing ceremonies and the athletics events at the 2024 Summer Olympics.
The pool stage of the 2009–10 Heineken Cup was the opening phase of the annual competition, in which 24 teams were arranged into six pools contesting of four teams each and then competed in a home-and-away double round robin.
 Eight teams, specifically the six pool winners and the two best runners-up, qualified for the quarter-finals, starting a knock-out phase that will end with the final at Stade de France in the Paris suburb of Saint-Denis.
The 2011–12 Heineken Cup pool stage was the first stage of the 17th season of the Heineken Cup, Europe's top competition for rugby union clubs.
 It involved 24 teams competing for eight quarter-final berths, awarded to the winners of each of six pools plus the two top-ranked second-place teams.
 The nest three best runners-up were parachuted into the Amlin Challenge Cup.
The 2011–12 Amlin Challenge Cup was the 16th season of the European Challenge Cup, Europe's second tier club rugby union competition.
 The tournament began with two matches on 10 November 2011 and ended with the final on 18 May 2012 at the Twickenham Stoop in London.
 A total of 23 teams from six countries participated—20 in the pool stage, plus three teams parachuting into the knockout stages from the Heineken Cup.
 In an all-French final, Biarritz claimed their first Challenge Cup, defeating Toulon 21–18.
 The Basque club claimed a place in the 2012–13 Heineken Cup, which will be their 13th consecutive appearance in Europe's top club competition.
The 2014–15 European Rugby Champions Cup pool stage was the first stage of the 20th season of European club rugby union, and the first to be organised under the new European Rugby Champions Cup format, which replaced the Heineken Cup as the top European competition for clubs.
The 2012–13 Heineken Cup pool stage was the first stage of the 18th season of the Heineken Cup, Europe's top competition for rugby union clubs.
 It involved 24 teams competing for eight quarter-final berths, awarded to the winners of each of six pools plus the two top-ranked second-place teams.
 The next three best runners-up were parachuted into the Amlin Challenge Cup.