Perennial of the Primulaceae family, this cultivar, like all members of the group, has its roots in Primula marginata, a species endemic to the Franco-Italian Maritime Alps, where it colonizes cliffs and crevices of limestone rocks between approximately 1,000 and 2,500 meters in altitude. 'Napoleon' is a well-established cultivar in specialized collections, mentioned in the literature of the Alpine Garden Society, although the precise history of its selection is not fully documented.
The foliage is medium green to grayish-green, covered with a moderate white farinose, more visible on the toothed margins than on the blade. The rosette is compact, spreading, with leaves of slightly rough texture. What distinguishes this cultivar at first glance is the variability of floral hue it seems to express depending on conditions or the stage of flowering: images show flowers ranging from a delicate light lilac to a fairly deep purple-violet, always with the characteristic white farinose eye of the species, well-defined and bright at the center of each corolla.
The flowers are borne in generous umbels on short stems, with wide, slightly notched petals, giving the umbels a full and rounded appearance. In its natural habitat, the species' flowering extends from April to June depending on altitude; in cultivation, this cultivar generally blooms in March-April.
It is cultivated in well-drained rock gardens or in pots with a slightly calcareous mineral substrate, sheltered from excessive winter moisture.