There are several ways to say "Nothing" in French: it all depends on the context in which the expression is used and the situation, which can be formal or informal.
Steps
Method 1 of 4: Common "Thank You" Answers
Step 1. If they thank you, respond by saying Je t'en prie, which literally means "Please"
You can hear the pronunciation here.
Step 2. When they thank you, you can also say De rien, which literally means "Of nothing"
You can use this phrase commonly to thank a person who holds the door open for you or who picks up a fallen object for you. You can hear the pronunciation here.
Method 2 of 4: Informal Expression
Step 1. To friends and family you can say Il n'y a pas de quoi or the short form, Pas de quoi
This is an informal way of saying "Don't worry". Literally it means "Nothing special". You can hear the pronunciation here.
Method 3 of 4: Formal Expression
Step 1. To strangers or people you are not familiar with, you can say Je vous en prie, which literally means "Please"
It allows you to make expressions like "The pleasure is mine". You can hear the pronunciation here.
Method 4 of 4: Saying "Say Nothing" when Giving a Gift
Step 1. When the person receiving the gift thanks you, say Avec plaisir, which literally means "With pleasure"
You can hear the pronunciation here.