This study deals with the productions of 8-to 10-year-old French-speaking children living in Paris area in a reading task and in semi-spontaneous speech. Two groups of speakers were recorded: pupils from an upper-class private school (10 girls / 8 boys), and children studying in a lower-class state school (8 girls / 10 boys). Mean fundamental frequency and F0 modulation were measured. Results show that girls from both schools presented a significantly higher average F0 than boys in both tasks. This difference was slightly more pronounced among children from the privileged school. No significant correlation was found between the speakers' height and their average F0, which rules out any physiological explanation. F0 modulation was significantly higher for girls in the privileged school but was very similar between both genders in the disadvantaged school. Regardless of gender, F0 modulation was stronger in children from privileged backgrounds, which suggests that a large modulation of pitch in French could be an upper-class marker. Overall, these data support the idea that pre-pubescent children would tend to develop gender-related vocal practices by adapting their pitch and their intonation in order to match the differences observed in adults.