Functional somatic syndromes, grouping somatic symptoms without an organic explanation, are defined either by their predominant symptoms or by an attribution to an, often hypothetical, cause. Due to many similarities, some authors consider that there is only one FSS due to a general phenomenon of "somatization". The objective of this work was to compare two functional somatic syndromes, one defined by its symptoms, fibromyalgia, and the other by a specific contested attribution, electro-hypersensitivity. Fibromyalgia or electro-hypersensitive participants (EHS) were recruited from September 2016 to April 2017 through associations of patients in Auvergne-Rhône-Alpes. Home interviews included the collection of medical, psychopathological, and symptom histories. The assessment of psychological distress, quality of life and the search for other functional somatic syndromes was performed through structured questionnaires, self-administrated scales, and clinical examination. Sixteen fibromyalgia subjects and sixteen EHS subjects were included. There are differences in symptomatology, although many symptoms are common to both conditions. Lifetime history of psychiatric disorders and current psychological distress and psychopathology are frequent in both groups but more prevalent in fibromyalgia subjects. The experience of the symptoms, their interpretation, the diagnostic itineraries and the therapeutic behaviours differ radically according to the group, even if for all socio-professional impact is high and quality of life are altered. The health status of fibromyalgia persons is overall worse than the health status of electro-hypersensitive individuals in this small sample. Despite the overlap in symptoms and a similar impact on daily functioning, this exploratory study suggests that heterogeneous mechanisms of "somatization" may be at stake in functional somatic syndromes.