Nous comparons les devis au lieu de les chiffrer.

Because comparons is the present tense form of comparer for nous.

For a regular -er verb like comparer, the present tense goes:

• je compare
• tu compares
• il/elle/on compare
• nous comparons
• vous comparez
• ils/elles comparent

So Nous comparons means we compare or we are comparing, depending on context.

It can mean either.

The French present tense often covers both:

• simple present: we compare
• present continuous: we are comparing

French usually does not need a separate form like English are comparing unless the speaker wants to emphasize the ongoing action in a special way.

Un devis is a quote, estimate, or cost estimate, especially in business or services.

For example, if a company tells you how much some work will cost before doing it, that is a devis.

A useful detail:

• un devis = one quote/estimate
• des devis = some quotes/estimates
• les devis = the quotes/estimates

Because devis is one of those French nouns whose spelling is the same in both singular and plural.

So you get:

• un devis
• des devis
• les devis

The article tells you whether it is singular or plural.

The two les are not doing the same job.

• In les devis, les is the definite article: the
• In de les chiffrer, les is a direct object pronoun: them

So:

• les devis = the quotes
• les chiffrer = to price them / to estimate them

This is very common in French: the same word can have different grammatical functions.

Au lieu de is a fixed expression meaning instead of.

It is made up of:

• à + le = au
• lieu = place
• de = of

Literally, it comes from the idea of in the place of, but in modern French you should just learn au lieu de as one expression meaning instead of.

Examples:

• au lieu de partir = instead of leaving
• au lieu du café = instead of the coffee

Because after au lieu, French uses de.

So the pattern is:

• au lieu de + noun
• au lieu de + infinitive

Here, what follows is a verb in the infinitive:

• chiffrer

So you get:

• au lieu de chiffrer
• and with the pronoun: au lieu de les chiffrer

Because les is an object pronoun, and in French object pronouns normally come before the infinitive they belong to.

So:

• chiffrer les devis = to price the quotes
• les chiffrer = to price them

This word order is very common:

• Je vais le faire = I am going to do it
• Il préfère les garder = He prefers to keep them
• au lieu de les chiffrer = instead of pricing them

You would not say chiffrer les here.

In this context, chiffrer means something like:

• to cost out
• to price
• to estimate financially
• to put a figure on

With devis, it usually has a business/financial sense.

Important: chiffrer can mean different things in different contexts. In some situations it can mean to encode/encrypt, but that is clearly not the meaning here.

French often uses an object pronoun to avoid repeating a noun phrase.

So instead of saying:

• au lieu de chiffrer les devis

the sentence says:

• au lieu de les chiffrer

This is more natural and less repetitive. English does the same thing:

• instead of pricing the quotes
• instead of pricing them

Because comparer can take a direct object.

So comparer les devis is normal French for compare the quotes.

If you want to mention two things explicitly, French can also say:

• comparer X et Y
• comparer X à Y

But when the meaning is simply compare the quotes, no extra preposition is needed after comparer.

This can feel a little different from English, where learners often think of compare X to/with Y. In French, comparer often works more directly.

Yes. In everyday spoken French, people often use on instead of nous.

So in conversation, you might hear:

• On compare les devis au lieu de les chiffrer.

That is very natural in speech.

But Nous comparons... is perfectly correct and more typical of careful or formal written French.