FILE - Then Bayern's head coach Julian Nagelsmann reacts during the Champions League, group C football match between Bayern Munich and Barcelona at the Allianz Arena in Munich, Germany, on Sept. 13, 2022. Photo: AP
Nagelsmann, 36, will take the reins for the European Championship next year, which is being hosted in Germany, the Bild daily said.
Flick became the first Germany coach in history to be dismissed from his post after his side slipped to a 4-1 friendly loss against Japan earlier in September.
Flick's men also failed to get out of the group stage at the World Cup in Qatar last year.
Germany have lost four of their six matches since then, as they prepare to host Euro 2024.
Nagelsmann has been out of work since he was fired by Bayern Munich earlier this year during a tight race for the Bundesliga title.
Nagelsmann had succeeded Flick in the dugout at the perennial German champions.
He was seen as a rising star after impressive spells as coach of German sides Hoffenheim and RB Leipzig.
Nagelsmann's name was mentioned as a possible candidate for a number of top club vacancies over the summer, being linked with English sides Chelsea and Tottenham Hotspur.
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