Short answer. Yes — you have become a partnership at will. Under Article 1785, when a fixed-term partnership is continued after its term without any express agreement, the partners' rights and duties stay the same, so far as consistent with a partnership at will. Simply carrying on the business without settling or liquidating is prima facie evidence the partnership continues.
What the law says
the rights and duties of the partners remain the same as they were at such termination, so far as is consistent with a partnership at will.
Civil Code, Article 1785 — Partnership Continued After Its Term. Read the full provision →
Carrying on turns it into a partnership at will
Article 1785 deals with what happens when a partnership set up for a fixed term, or for a single undertaking, keeps going after that term or undertaking has ended, and the partners never signed anything new. The article says that in that situation the rights and duties of the partners remain the same as they were at such termination, so far as is consistent with a partnership at will. In effect, the old fixed-term partnership has quietly converted into a partnership at will. The partners carry over their previous arrangement, but the fixed duration is gone, replaced by an arrangement that any partner can end at any time.
The presumption from just continuing
The second sentence supplies the evidence that this has happened. A continuation of the business by the partners... without any settlement or liquidation of the partnership affairs, is prima facie evidence of a continuation of the partnership. So no one has to prove a fresh agreement was made. If the partners — or those who habitually ran the business during the term — simply keep trading and never wind things up, that conduct is itself treated as proof the partnership carried on. 'Prima facie' means the presumption can be rebutted, but the burden shifts: a partner who says the firm ended must explain why continuing the business, without any liquidation, did not continue it.
What 'at will' changes
The conversion matters because a partnership at will is far less stable than a fixed-term one. During the original term, a partner who walked out early could be liable for breaking the agreed duration. Once the partnership has become one at will, that protection is gone: any partner may dissolve it at any time, in good faith, simply by giving notice. So partners who drift past their end date without noticing may find the firm now rests on nothing more durable than everyone's continued willingness to stay.
What to do if you drifted past your term
If your term has expired and you have kept trading, treat yourselves as a partnership at will and act accordingly. Decide deliberately whether to continue, and if you do, sign a fresh agreement — ideally a new fixed term — so you are not all one notice away from dissolution. If instead the venture has run its course, do the settlement and liquidation the article assumes did not happen: square the accounts, return or divide what is due, and record that the partnership has ended, so your continued dealings are not read as continuing a firm you meant to close.