To compare the efficacy of BF2.649 over placebo (12 week Double-Blind Phase) and assess the long term safety and the efficacy maintenance(9 months Open-Label Extension Phase) of BF2.649 in the improvement of excessive daytime sleepiness in patients diagnosed with Parkinson's Disease.

As measured by the change from baseline in the Epworth Scale Scores (ESS) at Week 12 and at Week 51, in patients diagnosed with EDS in Parkinson's Disease.

Inclusion Criteria:

• Patients with a documented history of Parkinson's disease according to UPDRS,fluctuator and non-fluctuator patients, Hoehn and Yahr score <5;
• stabilized on optimal antiparkinsonian treatments unmodified for 4 weeks prior to study entry;
• presenting an Excessive Daytime Sleepiness as indicated by an ESS>or=12

Exclusion Criteria:

• Patients with a known diagnosis of other degenerative parkinsonian syndromes (e.g. Progressive supra-nuclear palsy, multisystemic atrophy, corticobasal degenerescence, diffuse Lewy's Body dementia)
• Patients who have shift work, chronic or occasional sleep deprivation, circadian rhythm disorders
• Patients with a severe depression indicated by (BDI>= 16)or at suicidal risk (BDI item G>0) or depression treated for less than 8 weeks
• Patients with a cognitive impairment