Topi based his decision on a report by a parliamentary investigative committee earlier this month, which accused Sollaku, 45, of inadequately discharging his constitutional and legal functions and failing to take on organized crime.
"It cannot be denied that the prosecutor's office has not responded well to the phenomena of organized crime, corruption and crime in general, which has negatively affected the state's functioning and also created a lack of security for citizens' lives," the president's office said a statement.
The report said that Sollaku had failed to cooperate with international law enforcement agencies, had approved the release of 22 convicted criminals without cause, and had failed to act in serious criminal cases.
Opposition parties boycotted the committee's proceedings, accusing Prime Minister Sali Berisha's center-right Democratic Party of trying to seize control of the judicial system. They had voted against the report, which parliament approved by 77-37.
Sollaku, once Berisha's legal adviser, called his dismissal a "political farce" that violated the constitution.
Corruption and organized crime are rife in Albania, one of Europe's poorest countries.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969