Romantic obsession
The most obvious theme of the poem is the obsession that the God of Love instills in the narrator toward an object, in this case a rose, which is likely a metaphor for a woman. So the central idea of the poem can be said to be an exploration of the compelling experience of first love.
Free will and the influence of gods
By having divine forces in the poem (narcissus and cupid at least) asks the question, are we perfectly autonomous, or are we subject to forces from another realm—perhaps we are powerless against our divine "fate." This becomes especially clear as a theme in the second half, because Jean de Meun picks up on it and discusses it openly.
The meaning of a young man's life
As an allegory, the poem might come to represent adolescence, and although during the time, perhaps women would not have been treated quite the same way, the message definitely applies to everyone. Among the adolescent imagery are obsessive sexual attraction, the idea of fate or determinism, and the process of honing yourself through the resistance of temptation. These images are designed to show the 20 year old what his love life might feel like, an endless pursuit of an unattainable goal, much like a type of grail quest.
