conditional sentences

Hello there!
how would we say:
If you enter without permission, you are against the law.
or
If you enter without permission, you'll be against the law

second question:
Is it correct to write:
It is forbidden to take a chair from tha class.(what should we write in this case).
best Regards

[RonBee]

Say:

• If you enter without permission, you will be violating the law.

Say:

• It is forbidden to take a chair from the classroom.

:)