Short answer. No. Any partner may bring someone in to share his own portion of the partnership, but Article 1804 of the Civil Code says that associate is not admitted into the partnership itself without the consent of every other partner — even if the partner who brought them in is the managing partner.
What the law says
Every partner may associate another person with him in his share, but the associate shall not be admitted into the partnership without the consent of all the other partners, even if the partner having an associate should be a manager
Civil Code, Article 1804 — Sub-Partner (Associate). Read the full provision →
A private sharing arrangement, not partnership membership
The Civil Code lets every partner... associate another person with him in his share, meaning a partner can privately agree to split his own interest, profits, or losses with someone else. That arrangement is a matter between the partner and the person he brings in; it does not, by itself, touch the partnership or the other partners at all. What it does not do is turn the person brought in into a partner of the firm itself.
Admission as a partner needs everyone's consent
Article 1804 draws a hard line between sharing a portion and becoming a partner: the associate shall not be admitted into the partnership without the consent of all the other partners, even if the partner having an associate should be a manager. Partnership rests on the mutual trust of the people who agreed to be in business together, so the law will not let one partner unilaterally expand that circle, however small his own contribution or however senior his role. Unanimous consent of the other partners is what admission requires, not the say-so of the partner doing the associating.
What the associate does not get
Because he was never admitted as a partner, the associate has no rights against the partnership itself. He cannot demand to inspect the partnership's books, take part in managing its affairs, or act on its behalf, and the other partners owe him none of the duties partners owe each other. His rights run only against the partner who brought him in, under whatever private terms the two of them agreed — typically a share of that partner's own profits, not a claim on partnership property.
Being a manager does not change this
The article specifically anticipates the argument that a managing partner's broader authority to run the business day to day should let him also decide who joins the firm, and it rejects that argument in the same sentence. Managerial status controls ordinary business decisions, not the composition of the partnership. Admitting a new partner is treated as significant enough that it needs the other partners' actual consent, regardless of who is proposing it or what authority that person otherwise holds.