Leverkusen rebuild continues with Bade and Echeverri signings
Bade, 25, who made his debut for France in the Nations League in June, joined until 2030 for a reported fee of 25 million euros ($29 million).
"The Bundesliga and German football appeal to me a lot," Bade said. "It will be great fun to fight for titles here."
Echeverri, 19, joins Leverkusen on a season-long loan from Premier League club Manchester City.
The Argentine under-20 international joined City from River Plate in 2024 and scored for the English side in the Club World Cup.
Unbeaten league and cup winners in 2023-24, Leverkusen have undergone a rebuild this summer amid several high-profile departures.
Coach Xabi Alonso moved to Real Madrid while midfielder Florian Wirtz and wing-back Jeremie Frimpong both left for Liverpool.
Defender Jonathan Tah joined league rivals Bayern, midfielder Granit Xhaka joined Sunderland and captain Lukas Hradecky moved to Monaco.
On Thursday, Morocco winger Amine Adli signed with Premier League club Bournemouth, while striker Victor Boniface has been linked with a move to AC Milan.
Bade could line-up in central defence alongside English centre-back Jarell Quansah, who arrived from Liverpool this summer.