Thank you for your answers.
I have erased Random Events from the Mods folder and started a new game. As I met again the same problem I went to V9.
The game seems so much richer that I have to admit I am puzzled with the new Policy system and the new tech trees. I guess I will have to practice...
It seems I don't get happiness from exploited dye and silk tiles. I see I can get some (+1) from them with buildigs. Is that it all ?
For the moment, one of the main way to get happiness early game is to adopt Monarchy as your social policy. Monarchy gives +3 happiness for every garrisonned city. Other policies will give you less hapiness but are cumulative as long as you choose policy compatible with each other.
Then with Tech discovery some buildings giving happiness will be available to you. Especialy in the Economy tech tree and the building related to the luxury ressources you have.