Learn French: L'effervescence matinale commence dès la première heure. - The morning bustle begins from the very first hour.

While both can translate to "from" or "starting from", dès adds a strong sense of immediacy or earliness. It emphasizes that the bustle starts as early as or the very moment the first hour hits. À partir de is more neutral and just states the starting point.

Why use the adjective matinale instead of just saying du matin?

Saying l'effervescence du matin is completely correct and common in everyday speech. However, using the adjective matinale elevates the language slightly, making it sound more descriptive and elegant. You will often see this with other time-related adjectives, like une promenade nocturne (a night walk).

Does la première heure literally refer to 1:00 AM?

No, in this context, la première heure is a common expression that means "first thing in the morning" or the very beginning of the working day, not literally the first hour after midnight.

Could I say dès que la première heure here?

No, you cannot use dès que here. Dès que is a conjunction meaning "as soon as" and must be followed by a full clause with a subject and a conjugated verb (for example, dès que le jour se lève). Because la première heure is just a noun phrase, you must use the preposition dès by itself.