Comparing the two fragrances…

Calvin Klein

Courrèges
Obsession
In Blue
Only in Obsession
Shared character
Both Obsession and In Blue belong to the citrus family and share floral and woody accords. They both feature notes of jasmine, rose, bergamot, orange blossom, sandalwood, musk, vetiver, amber, mandarin, coriander, civet, and basil.
How they differ
Obsession is characterized by spicy, sweet, powdery, oriental, animalic, and warm spicy accords, utilizing unique notes of vanilla, oakmoss, incense, peach, green notes, spices, cedar, and frankincense. In Blue is characterized by chypre, green, and fresh accords, utilizing unique notes of tuberose, cedarwood, patchouli, green apple, violet, aldehydes, iris, moss, and pot marigold.
Who each suits
Obsession may suit those who prefer warm, spicy, and animalic oriental profiles. In Blue may suit those who prefer fresh, green, and chypre profiles.
More Obsession comparisons
Only in In Blue