The Foreign Ministry said that while it has confirmed the whereabouts of many Germans who were in the town of Sousse where the attack took place, they cannot confirm that no more Germans are among the dead.
A German woman was also seriously inured in the attack.
Interior Minister Thomas de Maizière will visit the site of the attack in which 38 people lost their lives, including at least one German.
De Maizière said that through his visit he hoped to showed his compassion for the victims and to stand with the people of Tunisia.
On Friday morning a 24-year-old student attacked a beach hotel in the resort town with a semi-automatic weapon. His assault ended when he himself was shot and killed.
The student is believed to have had Islamist sympathies. A Twitter post purporting to come from Isis took credit for the attack.
Foreign Minister Frank-Walter Steinmeier said on Saturday that he called his British counterpart Philip Hammond to express his sympathy for the British holidaymakers who lost their lives.
At least 30 British citizens have been confirmed as victims. Also confirmed among the dead are one Irish citizen, a Portuguese and a Belgian.
Tunisia and France attacks 'linked'
The head of Germany's internal security service said on Monday that there was an indirect connection between last week's terrorist attacks on a chemical factory in France and a holiday resort in Tunisia.
“Isis has long been calling for attacks to be carried out,” Hans-Georg Maaßen told ARD's breakfast television show Morgenmagazin.
“We already have the impression that the young man in Lyon had been influenced by IS, just as in Sousse,” he said.
There were ideological connections between the two which could be traced back to Isis, Maaßen added.