Le contrôle technique est valable à partir de demain.

In French, singular nouns usually need an article. So le contrôle technique is the normal way to say the technical inspection / the vehicle inspection.

You would not normally say just contrôle technique by itself in a full sentence here. French uses articles more often than English does.

Also, le shows that contrôle is masculine singular.

In everyday French, le contrôle technique often refers specifically to the official vehicle roadworthiness inspection, especially for cars.

Literally, the words mean technical inspection, but in real life it often has this specific administrative meaning. So if you see this sentence in France, it very likely means a car’s inspection certificate/status is valid from tomorrow onward.

Est valable means is valid or is acceptable/effective.

Here, valable is an adjective, and est is the verb être in the third person singular:

• est = is
• valable = valid

So the structure is very simple:

• Le contrôle technique = subject
• est = verb
• valable = adjective

French often uses être + adjective in places where English does too.

Both can relate to the idea of valid, but they are not always used in exactly the same way.

• valable often means valid, applicable, acceptable, or in force
• valide often means valid in a more formal/logical/official sense, and it can also mean able-bodied in other contexts

For documents, tickets, subscriptions, inspections, offers, and official periods, valable is extremely common:

• Le billet est valable jusqu’à dimanche.
• Votre passeport est valable dix ans.

So in this sentence, valable sounds very natural.

Literally, à partir de means starting from or from ... onward.

So:

• à partir de demain = starting tomorrow / from tomorrow onward

It marks the beginning of a period. The idea is not just tomorrow, but beginning tomorrow and continuing after that.

Because demain alone only means tomorrow, while à partir de demain means starting tomorrow.

Compare:

• Le contrôle technique est valable demain. = It is valid tomorrow.
• Le contrôle technique est valable à partir de demain. = It becomes valid starting tomorrow.

So the original sentence emphasizes the start of validity, not just one single day.

Yes. French word order is somewhat flexible here.

The most neutral version is:

• Le contrôle technique est valable à partir de demain.

But you could also say:

• À partir de demain, le contrôle technique est valable.

That version puts more emphasis on the time expression starting tomorrow.

Both are correct, but the original version sounds very natural and straightforward.

Because valable agrees with le contrôle technique, which is masculine singular.

The adjective valable has the same form in the masculine and feminine singular:

• un document valable
• une carte valable

In the plural, you add -s:

• des documents valables

So in this sentence, valable stays exactly as it is.

A rough English-friendly guide would be:

• contrôle ≈ kon-TROHL
• technique ≈ tek-NEEK

A few useful notes:

• the ô in contrôle is a long o sound
• the final -e in contrôle is not pronounced
• technique ends with a -neek sound
• the stress in French is much flatter than in English, usually falling toward the end of a rhythm group rather than strongly on one syllable

The full sentence is roughly: luh kon-TROHL tek-NEEK ay va-LABL ah par-TEER duh duh-MAN

That is only an approximation, but it can help at first.

Yes. Dès demain is possible and means something like as of tomorrow or starting tomorrow.

For example:

• Le contrôle technique est valable dès demain.

Compared with à partir de demain:

• à partir de demain is very explicit and neutral
• dès demain is a bit shorter and can sound slightly more immediate or emphatic

Both are natural, but à partir de demain is especially common in administrative or formal contexts.

Yes. French often uses the present tense with a future time expression when the meaning is clear.

Here, est valable is present tense, but à partir de demain tells you that the validity begins in the future.

English does something similar:

• The office is closed tomorrow.
• My pass is valid from tomorrow.

So there is nothing strange about using the present tense here. The time phrase makes the future meaning clear.