It is about history. France hope it will repeat itself, Portugal that they can create it. The hosts want 2016 to resemble 1984 and 1998 and to complete a hat-trick of major tournament wins on their own soil. Ninety-five years after their first international, the underdogs are looking to belatedly secure silverware.
But it is also about the future. A French victory would position them to take over from Germany and Spain as the dominant European team of their era.
Their ageing full-backs should not make Russia in two years' time but the rest of Didier Deschamps' team could: If they go east as European champions, they might be favourites to lift the World Cup.
Portugal, with a team spliced together from emerging and declining generations, would not be. By 2018, Cristiano Ronaldo will be 33, Jose Fonte 34 and Pepe 35. This is not the start of something as much as a one-off.
Their progress has been unexpected, the product of tenacity as much as anything else.
Tactically, they play like the outsiders they are. They will defend deep to negate Antoine Griezmann's pace. They will keep men behind the ball, challenging France to break them down.
Tellingly, their most technical midfielder, Joao Moutinho, is likely to start on the bench. They prefer the defensive bulwark William Carvalho, the all-action Renato Sanches, the indefatigable Adrien Silva and the understated Joao Mario.
They assume a compact shape. Perhaps Portugal could be outflanked, but France are less likely to do that. Moussa Sissoko is a central midfielder operating on the right. On the left, Dimitri Payet tends to cut infield to use his favoured foot. It could create opportunities for overlapping full-backs, but Patrice Evra and Bacary Sagna are less dynamic than they once were.
It all suggests the pivotal part of the pitch will be just in front of the back four where Carvalho will try and crowd out Payet and Griezmann. If both are subdued, the onus falls on France's central midfielders, whether on Blaise Matuidi to pick a pass through a packed defence or on Paul Pogba to surge forward himself, in a bid to make something happen.
That carries risks for both sides. Portugal prefer to operate on the counter-attack, aided by Sanches' power. Their forward line consists of two wingers in Ronaldo and Nani. They have no focal point, rather two opportunists who can roam.
There will be times when the French centre-backs will have no one to mark. This is nevertheless a test of both their concentration and their aerial ability. Ronaldo's remarkable header in the semi-final against Wales highlighted his leap.
While Samuel Umtiti has impressed, there is still a suspicion France are susceptible to crosses. Portugal's are likeliest to come from full-backs Cedric Soares and Raphael Guerreiro. They are likely to adopt safety-first tactics.
France will probably be bolder. Deschamps is trying to cram 12 players into his starting 11. As in the semi-final against Germany, defensive midfielder N'Golo Kante will probably be the odd man out, a substitute to introduce if France have a lead, should Deschamps' 4-4-2 - which means the prolific Griezmann can play in his preferred central role - work.
If not, the probable replacement would be winger Kingsley Coman, who has the pace and skill to stretch defences.
Portugal can call on Ricardo Quaresma, who has proved a strangely talismanic replacement. Drama tends to be either rationed or delayed in their games. They have won only once inside 90 minutes. They are the tournament's most annoyingly obdurate side, France its top scorers.
It sets up a duel between defence and attack, defiance and adventure, a team looking for an achievement that eluded any of their predecessors and one trying to ensure they do not come up short compared to earlier generations. France are the favourites, but Portugal will be galvanised if they are written off.