The event is scheduled to take place from January 25 to February 2.
It is common to see national flags and the flag of the Communist Party of Vietnam on Hanoi's streets.
The flags on Kim Ma and Nguyen Chi Thanh streets.
Banners feature messages about the congress.
On Dai Co Viet Street, Hai Ba Trung District
The national flag on the Square of August Revolution in Hoan Kiem District.
On Dinh Tien Hoang Street
Around 400 banners installed around Ba Dinh Square, Hung Vuong Street and Doc Lap, Chu Van An and Le Hong Phong streets.
The decoration work would be finished on January 15. Lights and flowers will also be used for the decoration.