All three nations went into Friday night's action with their fates firmly in their own hands and knowing that victory would seal their place on the plane next summer.
At one stage it looked as though they would all hold up their end of the bargain in fairly routine fashion, but fightbacks from their opponents in each match made things a little more nail-biting than they otherwise might have been.
However, Portugal and Belgium both held out for 3-2 wins against Slovakia and Austria respectively, while France overcame fellow European heavyweights Netherlands 2-1 in Amsterdam.
Cristiano Ronaldo scored twice on his 202nd appearance for Portugal to become the first male player to hit 125 international goals for his country.
Goncalo Ramos had already given Roberto Martinez's side the lead in the 18th minute before Ronaldo's brace, the first of which came from the penalty spot and the second of which came from close range after Bruno Fernandes had played a low ball across goal.
Portugal's proud record of not having conceded in qualifying before tonight was ended three minutes before Ronaldo's second goal when David Hancko briefly halved the deficit for Slovakia, and Stanislav Lobotka again pulled it back to one goal 10 minutes from time.
The visitors could not find an equaliser in Porto, though, and it was a similar story for Austria in their winner-takes-all showdown with Belgium.
The top two sides in Group F went into the match knowing that the winners would qualify, and Belgium appeared to be cruising towards that fate when they took a 3-0 lead in Vienna.
Dodi Lukebakio's first two international goals either side of half time put them in command before Euro 2024 qualifying top-scorer Romelu Lukaku continued his prolific form this season with a third.
Austria came fighting back in the final 20 minutes though, with Konrad Laimer giving them hope in the 73rd minute before Marcel Sabitzer converted from the penalty spot 11 minutes later.
Belgium's Amadou Onana was also sent off between those two goals to further boost Austria's hopes of a remarkable comeback, but the visitors held on to book their place in Germany.
World Cup runners-up France will join Portugal and Belgium at next summer's tournament thanks in no small part to Kylian Mbappe, who put in a star showing in their victory over Netherlands.
The Paris Saint-Germain forward scored twice to move level with Michel Platini in his nation's all-time goalscoring ranks, with Netherlands only managing an 83rd-minute Quilindschy Hartman goal in reply.
Hosts Germany are the only other nation to be guaranteed a place at next summer's tournament so far, although more teams could join the already-qualified quartet in the second round of fixtures during this international break.