Sans badge, je ne peux pas entrer dans l’immeuble, alors j’en garde toujours un de secours dans mon sac.

After sans (without), French often leaves out the article when speaking in a general sense.

So:

• sans badge = without a badge
• sans argent = without money
• sans problème = without a problem / no problem

You can sometimes see an article after sans, but here sans badge is the normal, natural way to say it.

In standard French negation, ne ... pas goes around the conjugated verb.

Here the conjugated verb is peux from pouvoir:

• je peux = I can
• je ne peux pas = I cannot / I can’t

Then entrer stays in the infinitive because it follows pouvoir:

• je peux entrer = I can enter
• je ne peux pas entrer = I can’t enter

This is a very common pattern:

• je veux partir = I want to leave
• je ne veux pas partir = I don’t want to leave

In French, entrer often needs dans when you say what place someone is entering.

So:

• entrer dans l’immeuble = enter the building
• entrer dans la pièce = enter the room
• entrer dans la voiture = get into the car

English often says simply enter the building, but French usually prefers entrer dans + place.

Immeuble begins with a vowel sound, so the article le contracts to l’:

• le bâtiment
• l’immeuble

This happens with le or la before a vowel or mute h:

• l’école
• l’hôtel
• l’amie
• l’homme

So dans l’immeuble means into the building.

Yes, here immeuble means building, especially a block of apartments or a larger urban building.

Depending on context, immeuble can suggest:

• an apartment building
• a residential block
• a multi-unit building

It is a very common word in everyday French.

Here alors means something like so, therefore, or as a result.

The logic is:

• Sans badge, je ne peux pas entrer dans l’immeuble
• alors
• j’en garde toujours un de secours dans mon sac

So the speaker is saying: Without a badge, I can’t get into the building, so I always keep a spare one in my bag.

In other contexts, alors can also mean then.

French shortens je to j’ before a vowel sound or mute h.

Since en begins with a vowel sound, you say:

• j’en garde not
• je en garde

This is the same pattern as:

• j’ai
• j’habite
• j’aime

Here en replaces the noun already mentioned: badge.

So instead of repeating badge, French uses en:

• Je garde un badge de secours dans mon sac.
• J’en garde toujours un dans mon sac.

In English, we would often say I always keep one or I always keep one spare. French uses en to mean of them / one of those / some of that, depending on context.

Because un is still present, en does not mean one by itself here. It just stands for the noun badge.

De secours is a fixed expression meaning spare, backup, or for emergency use.

So:

• un badge de secours = a spare badge / backup badge
• une clé de secours = a spare key
• une sortie de secours = an emergency exit

In the sentence, j’en garde toujours un de secours means I always keep a spare one.

French adverbs such as toujours, souvent, and déjà are often placed after the conjugated verb.

So:

• je garde toujours = I always keep
• il mange souvent = he often eats
• nous avons déjà fini = we have already finished

That is why you get:

• j’en garde toujours un de secours

not usually:

• j’en toujours garde...

Because badge is masculine in French:

• un badge

When en replaces badge, the sentence still shows the gender through un:

• j’en garde toujours un

If the noun were feminine, you would use une:

• une clé
• j’en garde toujours une

Both verbs are in the present tense:

• je peux = I can
• je garde = I keep / I am keeping

In this sentence, the present tense expresses a general fact or habit:

• Without a badge, I can’t enter the building
• so I always keep a spare one in my bag

French often uses the present tense for habits, just like English does.

Yes. Badge is used in French, especially for an access pass, ID badge, or electronic entry badge.

Depending on context, French might also use words like:

• carte d’accès = access card
• carte magnétique = magnetic card
• pass = pass

But badge is completely normal here, especially for a building entry badge.

Yes, absolutely. That would also be correct.

Compare:

• Je garde toujours un badge de secours dans mon sac.
• J’en garde toujours un de secours dans mon sac.

The second version sounds a bit more natural in connected speech because it avoids repeating badge after it was already mentioned. French often likes this kind of pronoun replacement.

It simply means in my bag.

• dans = in / inside
• mon sac = my bag

French uses mon here because sac is masculine:

• un sac
• mon sac

So the phrase is straightforward: the speaker keeps the spare badge inside their bag.