Hi @Amanda2878
First...so sorry this is happening to you. This situation is becoming more and more common, especially in California where housing law favors the tenant and evictions can become long and drawn out. Meanwhile you are being fined and the tenant is collecting money while you try to get them evicted. Be sure to keep good records of all your phone calls and documentation of the below:
Good advice from @Shelley159 to report the listing using the flag icon:
You can also report the fake "Host." Scroll down to the bottom of the Listing page and you'll see "Meet your Host" with a picture of them. Click the picture and you'll see some info about them and a small flag that says "Report This Profile." Click that:
Per @Mike-And-Jane0 , Airbnb normally will not be very helpful, as they do not get involved with these types of issues unless a guest of this person reports them and asks Airbnb for a refund for listing inaccuracy (they list amenities not available to them, or parking issues, or they direct them to a different address etc.).
I agree with @Kia272, since fines are being imposed, you will need to get an attorney ASAP to start the evicition process. Hopefully you have a lease agreement that states the tenant may not sublease, including on platforms such as Airbnb? You can also have your attorney draft a letter to the tenant advising them to cease and desist while the eviction process is ongoing.
In the mean time, I would send a certified letter to the city (include copies of the fine letters you received and your lease agreement with this tenant) explaining you have a tenant in the property illegally listing the property on Airbnb and are in the process of having them evicted. I would also send copies of all this via certified mail to Airbnb's corporate headquarters.
I would also report this as fraud to the LA County District Attorney's office. Give them a call and ask what the process is to report this activity. Assuming you did a background check, you should know where this person is employed. You can contact their employer and advise them what their employee is doing (fraud). Be prepared for possible damage to your property and repercussions, so I would start with advising the tenant you are aware of the illegal activity and to cease and desist immediately. Even if they stop renting on Airbnb, they could still cause you alot of grief while the eviction process is ongoing; especially if they get fired for committing fraud. If they get fired, that's even more of a reason to continue illegally collecting money on Airbnb, since they won't have an job/income. This could backfire.
You could also consider reporting this to the media, but I would first send your letter to Airbnb and give them the opportunity to take action. If they don't, your attorney can advise you if this is a good idea or not.
Again, so sorry this is happening. Do keep us informed of how it goes.