  Let $(\mathcal C,\otimes,\mathbb 1)$ be an abelian symmetric monoidal
category satisfying certain exactness conditions. In this paper we define a
presheaf $\mathbb P^{n}_{\mathcal C}$ on the category of commutative algebras
in $\mathcal C$ and we prove that this functor is a $\mathcal C$-scheme in the
sense of Toen and Vaqui\'e. This construction gives us a context of
non-associative relative algebraic geometry. The most important example of the
construction is the octonionic projective space.
