I confirm!
it's a "propusk", or a pass, for access to red square "krasnaya plochtchad", for day of international fest of workers, 1er mai de l'année 1951. For the tribune A, signed by general-lietenant Vladik, for Boris Nikolaievitch Ponomarev.
My item to detect fakes is to check if writen with china ink. But yours looks nice.:p
As was mentioned, this a pass to the Red Square tribune, that was on the left and right sides of the Mausoleum. It was given to those who were not senior enough in the party and Government to stand on the Mausoleum itself, and to KGB officers in charge of the security. I believe tribune "A" was reserved for more important people.
This pass is to Boris Nikolaevitch Ponomarev, who in 1951 was only deputy department chief in the Central Commitee of the CP, but later became member of the Politburo and deputy of the Supreme Soviet. He was considered a specialist in the Party history and international workers movement. Of course he was also a Hero of the Socialist Labor.
On, the document is not personaly signed, but authorised by Vlasic, Stalin's personal assistant and chief of security.