BTW, it must be noted that this sentence is actually not very grammatical. (I can't report it because I'm not taking this course).
If you wanted to say "I like blue literature", "Mavi edebiyatı severim" would be correct.
But if you want to say "I like French literature", you do NOT say "Fransız edebiyatı severim", you MUST say "Fransız edebiyatını severim".
"Fransız edebiyatı" is an "isim tamamlaması (compound noun)" in Turkish so you MUST add "ismin -i hali" to it when you "like" it. So when used as the object of this verb (sevmek), it should be used as "Fransız edebiyatıNI".