Note also that if you cannot show documentary proof of an
Indian ETA at check-in at SIN for a ticket to India you may be refused travel...
Note that
this page seems to suggest that the Visa on Arrival must now be applied for via the ETA channel above, and 4 days before travel, so there does not seem to be a Visa on Arrival facility any more (not that it was open to French citizens to begin with, if that is your nationality)
As you are travelling to India, they *should* check your entitlement to travel there rather than leaving it to CDG....