Algerian authorities had previously said Tebboune was in Germany for medical checks when he flew there last week, after saying people in his administration had the coronavirus.
Tebboune, 75 and a smoker, was elected less than a year ago as Algeria faced its biggest political crisis in decades with a mass protest movement demanding the entire ruling class be replaced.
Backed by the powerful military, he pushed for changes to the constitution as part of a strategy to turn the page on the unrest. But though it was approved in a referendum on Sunday, voter turnout of 23.7% was very low.
His absence through illness could slow Algeria's efforts to meanwhile pass economic reforms aimed at reducing the reliance on dwindling energy revenues. (Reporting by Lamine Chikhi; Writing by Angus McDowall; Editing by Alex Richardson)
epa08770336 (FILE) - Algerian President-elect Abdelmadjid Tebboune speaks during a press conference in Algiers, Algeria, 13 December 2019 (reissued 24 October 2020). According to a presidency press release, Algerian President Abdelmadjid Tebboune will start a five-day voluntary quarantine as per medical staff of the presidency advice after senior officials showed symptoms of Coronavirus infection. EPA-EFE/MOHAMED MESSARA 