French and English have completely different systems for capitalizing words in titles.
In English, there are several systems that differ slightly; they are all along the lines of: capitalize the first and last words and all other words in the title except conjunctions, prepositions, and articles. For example:
The Tall Blond Man with One Black Shoe,
The Lion, the Witch, and the Wardrobe.
In French, there are also several systems you can use, as described in the answers to this question. You always capitalize the first word. In one system, you leave the rest lowercase. In another common system, if the first word is a definite article, you capitalize the first noun, any adjectives before it, and any nouns on an equal footing with it (e.g., joined to the first noun by et or ou).
Le Grand Blond avec une chaussure noire,
Le Lion, la Sorcière blanche et l'Armoire magique.
I don't believe any of the French systems would capitalize française in Langue française, as it comes after the noun it modifies.