A319 Flight Attendant reported gate agent boarding the aircraft early on two separate occasions; catching the cabin crew off guard and violating their contract.

Narrative

Briefed with the gate agent regarding boarding time. He told me that they were told to board early; not on time.. 30 mins prior to departure. I told them that not only is it a contract violation for the flight attendant's but it is an unsafe practice to board early when we are not yet in position to properly board the aircraft in our boarding locations. The gate agent called his supervisor who returned to the gate only to inform him that it was a directive from the company and would be followed regardless of the above repercussions. The union informed me to file reports every time the company/gate agents board early despite briefing with them that we board on time only. Not late. Not early. On time. Please help communicate to the company that it is important that we follow the contracts and safety guidelines that have been established for years with regards to boarding aircraft as scheduled. This also happened again on today's flight ... boarding 2 minutes early despite briefing that we'd board on time and catching the crew off guard yet again.