Your question depends heavily on definition of the word modern. "Modern" when used with fragrance reminds me of modern art as opposed to more traditional art styles. Traditional art is usually representational, depicting people, nature, or events in history that the artist thought was significant or represented an aspect of visual beauty. Traditional fragrances also model nature to smell like beautiful things from the world such as citrus, green plants, flowers, leather etc. "Modern" fragrance like modern art would be to use things from nature like natural essences or synthetic mimicry of natural scents to mix together into abstraction or an all new structure of things that is not a naturally occuring fragrance. Many fragrances today are "modern" in that they create scents that are far from just mimicking nature or real scents in the world but take things to an all new level of creation by use of balance, harmony, rhythm, and design in the mix of ingredients. Examples of modern fragrances are Gucci pour Homme, M7, Acqua di Gio, etc. Most fragrances today are "modern" designs.
Following modern art styles there is post-modern art which is different from modern art in that postmodern artists use images of the real world or actual objects from the world that are still kept in their "real" form, but combined in an abstract way. Post modernism began with pop art in the lat1960's and continues today as the most prominent art style. Post modernism in fragrance design also use images from the world combined in an abstrat way. Examples of postmodern fragrances are Comme des Garcons synthetics like odor 53, Garage, Dry Clean, Soda, and Tar. The CdG incenses are also postmodern in design. Other postmodern fragrances are the Demeter Fragrance Library and many of the Ava Luxe scents.
Am I overthinking this? It may be easier to just say that anything is modern that is not traditional!?