When was the first Constitution of Vietnam born?

Our country's first law was passed at the 2nd session of the 1st National Assembly with 240 votes in favor and 2 abstentions.

1946

After the success of the August Revolution, on September 2, 1945, President Ho Chi Minh read the Declaration of Independence, giving birth to the Democratic Republic of Vietnam.
On September 3, 1945, at the first meeting of the Provisional Government , President Ho Chi Minh raised the issue of the need for a democratic Constitution for Vietnam.
Despite the extremely difficult conditions of the early days of independence, the Provisional Government at that time still successfully organized the General Election to elect the first National Assembly on January 6, 1946.
After 10 months of active preparation, under the close direction of President Ho Chi Minh, on November 9, 1946, the 1st National Assembly (2nd session) officially passed the first Constitution of our country (with 240/242 votes in favor), which was the 1946 Constitution.
The Constitution was adopted, marking the declaration of Vietnam's independence from North to South, under the people's democratic regime, the power in the country belongs to all the people regardless of race, gender, rich or poor, class, religion; democratic freedoms are guaranteed...
The 1946 Constitution was a strong legal affirmation of the national sovereignty of the Vietnamese people, the independence and territorial integrity of the Democratic Republic of Vietnam. However, due to war conditions, the 1946 Constitution was not officially promulgated. However, the spirit and content of the 1946 Constitution were always applied by the Provisional Government and the Standing Committee of the National Assembly to govern the country. The constitutional ideology of the 1946 Constitution was always inherited and developed in later Constitutions.

Source: https://vtcnews.vn/hien-phap-dau-tien-cua-viet-nam-ra-doi-nam-nao-ar929771.html