Ce matin, j’ai fait une petite erreur dans mon courriel, mais Marie l’a remarquée tout de suite.

Ce matin means this morning and is a very common time expression in French.

• Ce matin = this morning
• Aujourd’hui = today
• Ce matin-là = that morning / that particular morning

Here, Ce matin is the natural choice because the sentence refers to something that happened earlier the same day or in a context where this morning makes sense.

Also, French often puts time expressions at the beginning of the sentence for emphasis or smooth flow:

• Ce matin, j’ai fait...
• Aujourd’hui, je travaille...

Both are normal.

J’ai fait is the passé composé, which is the most common tense in spoken and everyday written French for a completed action in the past.

So here:

• j’ai fait une petite erreur = I made a small mistake

Why not the others?

• je faisais is the imparfait, used for ongoing, repeated, or background actions in the past. It would not fit as well for one completed mistake.
• je fis is the passé simple, a literary tense mostly found in novels and formal historical writing, not normal conversation.

So j’ai fait is the natural everyday form.

French commonly uses faire une erreur to mean to make a mistake, just as English says make a mistake.

• faire une erreur = very common, natural, everyday
• commettre une erreur = also correct, but a bit more formal or serious in tone

So:

• J’ai fait une petite erreur sounds very natural.
• J’ai commis une erreur is possible, but it sounds more formal and sometimes heavier.

For a learner, faire une erreur is the safest and most useful expression.

In French, most adjectives come after the noun, but some common short adjectives often come before it. Petit/petite is one of them.

So:

• une petite erreur = correct
• une erreur petite = unnatural here

This follows a common pattern with adjectives like:

• petit
• grand
• jeune
• vieux
• beau

A useful memory trick is that many frequent adjectives of size, age, beauty, and goodness come before the noun.

Dans mon courriel means in my email and is the natural choice here because the mistake is inside the content of the message.

• dans = in / inside
• sur = on, which usually would not fit here

So:

• une erreur dans mon courriel = a mistake in my email

As for the noun:

• courriel is a standard French word for email
• email or mail is also heard, depending on region and context

Regional note:

• In Quebec, courriel is especially common.
• In France, people often say mail in everyday speech, though courriel is perfectly correct.

French often contracts words when one ends in a vowel and the next begins with a vowel sound. This is called elision.

So:

• je ai becomes j’ai
• le a or la a becomes l’a

This avoids awkward vowel contact.

Examples:

• j’aime
• j’habite
• l’homme
• l’a vue

In your sentence:

• j’ai = je ai compressed
• l’a remarquée = la a remarquée compressed

Here, l’ stands for la, referring back to une petite erreur.

So the structure is:

• Marie a remarqué l’erreur
• replaced with pronoun: Marie l’a remarquée

Because erreur is:

• singular
• feminine

the direct object pronoun is la, which becomes l’ before a vowel.

So l’ = it, specifically referring to the mistake.

This is one of the most important grammar points in the sentence.

The verb is remarquer in the passé composé with avoir:

• Marie a remarqué

Normally, with avoir, the past participle does not agree with the object.

But it does agree when a direct object comes before the verb.

Here:

• l’ comes before a remarquée
• l’ refers to une petite erreur
• erreur is feminine singular

So:

• base form: remarqué
• feminine singular agreement: remarquée

That is why we get:

• Marie l’a remarquée

Compare:

• Marie a remarqué l’erreur. → no agreement shown before the verb
• Marie l’a remarquée. → agreement because the direct object comes first

Because in j’ai fait une petite erreur, the direct object une petite erreur comes after the verb, not before it.

With avoir, the past participle usually agrees only when the direct object is placed before the verb.

So:

• J’ai fait une erreur. → fait stays unchanged
• L’erreur que j’ai faite... → now faite agrees, because l’erreur comes before ai faite

That is why:

• j’ai fait une petite erreur but
• Marie l’a remarquée

Not exactly.

• voir = to see
• remarquer = to notice

Remarquer suggests that Marie specifically noticed the mistake, not just saw it physically.

So:

• Marie l’a vue = Marie saw it
• Marie l’a remarquée = Marie noticed it

In this sentence, noticed is the better match.

Here, tout de suite means right away or immediately.

So:

• Marie l’a remarquée tout de suite = Marie noticed it immediately

In modern everyday French, tout de suite very often means immediately.

Be careful, though: in some contexts learners confuse it with right after in a sequence. Usually the intended idea is still without delay.

Examples:

• Je viens tout de suite. = I’m coming right away.
• Il a compris tout de suite. = He understood immediately.

The comma is used to separate the two parts of the sentence:

• Ce matin, j’ai fait une petite erreur dans mon courriel
• mais Marie l’a remarquée tout de suite

This is similar to English, where a comma often appears before but when joining two full clauses.

It also helps the sentence read more smoothly.

The first comma after Ce matin is also common because the time expression has been moved to the front:

• Ce matin, ...

In careful speech, it would sound something like:

Ce matin, j’ai fait une petite erreur dans mon courriel, mais Marie l’a remarquée tout de suite.

A few pronunciation points:

• Ce matin: the e in ce is often very light
• j’ai sounds like zhay
• fait sounds roughly like feh
• petite sounds like puh-teet
• erreur has the French r sound
• l’a is very short: la
• tout de suite sounds roughly like too duh sweet

Also, in natural speech, French flows a lot, so words connect smoothly.

Grammatically, yes, but the meaning changes.

• mais = but
• et = and

Here, mais shows contrast:

• I made a small mistake, but Marie noticed it right away.

That contrast matters because it highlights the second idea as unexpected or significant.

If you said:

• ... et Marie l’a remarquée tout de suite it would simply add information, without the same contrast.

So mais is the better choice here.

Courriel is masculine:

• un courriel
• mon courriel

That is why the sentence says:

• dans mon courriel

If it were feminine, it would be ma instead of mon.

A common learner difficulty is that erreur is feminine but courriel is masculine, so the sentence contains both:

• une petite erreur → feminine
• mon courriel → masculine

The order is:

subject + object pronoun + auxiliary + past participle + adverbial phrase

So here:

• Marie = subject
• l’ = direct object pronoun
• a = auxiliary
• remarquée = past participle
• tout de suite = adverbial expression

French object pronouns usually come before the conjugated verb:

• Marie remarque l’erreur
• Marie la remarque
• Marie l’a remarquée

That placement is very important in French.