| Statistic | Saint-Sébastien | Quebec | National |
| Population | 645 | 8,565,732 | 38,134,230 |
| Population density (sq km) | 11 | 6 | 4 |
| Median age | 42.0 | 42.6 | 40.9 |
| Male/Female ratio | 1.0:1 | 1.0:1 | 1.0:1 |
| Married couples | 47% | 50% | 66% |
| Families w/ kids at home | 41% | 40% | 43% |
| Speak English only | 1.6% | 4.7% | 68.8% |
| Speak French only | 63.6% | 49.5% | 4.5% |
| Data | Percent |
| Latin American | 0.1% |
| N/A | 0.0% |
| Data | Percent |
| Other Western Europe | 1.8% |
| Chile | 0.7% |
| Japan | 0.1% |
| Mexico | 0.1% |
| Algeria | 0.1% |