Some anti-Syrian politicians in Lebanon have accused Syria of being behind the bombing, a claim that Damascus denies.
The court will have 60 days from when the prosecutor takes office to ask the Lebanese authorities to transfer people and evidence.
One woman at Hariri’s memorial in Beirut said: “There will be no life in Lebanon and no place for security if this court fails to prosecute Hariri’s killers.”
The court was set up at Lebanon’s request, and will have a budget of about 40 million euros. It’s expected to take three to five years to finish its work.
Another man in Beirut said: “This is a great day for us, one we’ve eagerly awaited. We want the court to waste no time and to quickly reach a verdict.”
If charges are laid, suspects can surrender voluntarily, the court can ask the Security Council to put pressure on states to send people to the court, or it can try suspects in absentia.
Hariri case could take up to five years