Originally Posted by
IstKong
Not that easy.
We have a lot of posts here saying that airlines are very reluctant to board anybody who does not hold the proper passport these days.
For instance, check this experience boarding a flight from the US to AMS :
https://www.flyertalk.com/forum/32484708-post612.html
I would not be surprise to hear that he was not able to start his journey to Croatia even with the proper documents.
To board to CDG, there are big chances that the airline will request the "attestation". He will tick the 4th box, and then, the airline may ask him a proof that Croatia is the country of "origin"... There is a high probability that he will not make on board the flight to CDG because of the airline rigidity, even if he is clearly allowed to travel through CDG (which is unclear : transit being a reason to be required to produce the certificate).
The "transit" mention on the attestation is enough for the airline to not take the risk allowing him on board.
We don't know OP's citizenship and reasons for travel. If OP is eligible to travel to Croatia based on his/her citizenship or for a valid reason as published by Croatia, there is no reason for OP to not be allowed to transit in CDG. OP may indeed need whatever form French bureaucracy seems to enjoy since beginning of Covid crisis but those forms are easy to find on the airline or government websites and it takes 5 min to fill. Another important condition I mentioned is to have all flights on a single ticket. If all conditions are not met, indeed the airline can deny boarding, but at that point there is nothing in OP story allowing us to make such a conclusion.