The Lord Mayor Christy Burke and the Taoiseach Enda Kenny are among the first people to sign the book of condolence for the victims of the Germanwings plane crash.
A book has opened at the Mansion House this morning for people who want to pay their respects for the 150 people who died on board.
Members of the public will be able to offer their condolences between 11 o'clock and 4pm today.
Christy Burke, says the book will remain open until Saturday.
Meanwhile according to US meda, one of the pilots of the plane that crashed in the French Alps was locked out of the cockpit before it started its descent.
Investigators have not revealed details of conversations on the cockpit voice recorder recovered from the crash site.
But the New York Times has quoted a senior military source involved in the investigation.
Sky's Europe Correspondent Robert Nisbet is in Seyne, near the remote crash zone:
