When we talk about proficiency it simply means what you can DO with the language. Not necessarily how much you know in your head, but what can you do with the language to COMMUNICATE. For example, I can ask for someone's name and give my name. That's a measure of proficiency.
In other words, proficiency refers to the degree of skill with which a person can use a language to understand, speak, read and write in real-life situations.
Check out this graphic to see what the Path to Proficiency looks like at a high level:
The state of Texas has set proficiency targets for each of the 3 modes of communication for each level of French. The 3 modes are:
Interpersonal Speaking (2-way written or spoken conversation)
Presentational Speaking (1-way written or spoken communication)
Interpretive Reading and Listening
French 1 - Novice Mid to Novice High
French 2 - Novice High to Intermediate Low
French 3 - Intermediate Low to Intermediate Mid
French 4 - Intermediate Mid to Intermediate High
French 5 - Intermediate High to Advanced Low