"The boy has a warm jacket."
Translation:Le garçon a une veste chaude.
Standard adjectives are placed after the noun. Generally speaking, only the so-called BANGS adjectives are placed before the noun. There are a few exceptions where an adjective has a different meaning depending on its placement, but this is not one of them.
- Beauty : C'est une belle femme (she is a beautiful woman)
- Age (e.g., new, old) : J'ai une nouvelle voiture (I have a new car)
- Number : Il y a vingts canards (There are twenty ducks)
- Goodness/Badness = C'est un mauvais garçon (He's a bad boy)
- Size : Ce sont de grosses pommes (these are big apples)
For those who have asked or are wondering, in French most adjectives go after the noun.
There are a few adjectives which go before the noun. These are sometimes called the BANGS adjectives, which stands for Beauty Age Numbers Goodness Size.
It's more a can of worms than you can imagine. It's true that many people use "coat" and "jacket" interchangeably. In French, however, "un manteau" is definitely not considered to be a jacket. It refers to a large and very often a long coat that extends to the mid-calf or even below. It is also referred to as an overcoat. Maybe thinking "overcoat" when you see manteau will help you remember. So the trick is to use the word closest in meaning to the French, not our preferred interchangeable English.
In French, most of the time the adjective goes after the noun, but in certain cases, such as BANGS (beauty, age, numbers, goodness, size) the adjective goes before the noun. There are also cases when putting the adjective before or after the noun affects the meaning. An example would be "Un grand homme" ( A great man) and "un homme grand" ( a tall man). Here are two websites about adjectives that can help you. https://www.cliffsnotes.com/study-guides/french/french-i/french-i-adjectives/adjective-placement-within-sentences https://www.dummies.com/languages/french/how-to-place-of-french-adjectives-correctly/
I hope this helps :)