Short answer. The owner. Article 608 of the Civil Code gives the owner the full insurance indemnity in case of loss when the usufructuary refused to contribute to the insurance and the owner insured the tenement alone, subject only to whatever right the usufructuary retains under the preceding article.
What the law says
Should the usufructuary have refused to contribute to the insurance, the owner insuring the tenement alone, the latter shall receive the full amount of the insurance indemnity in case of loss, saving always the right granted to the usufructuary in the preceding article.
Civil Code, Article 608 — Shared Insurance. Read the full provision →
Why refusal to contribute changes the outcome
Article 608 contrasts sharply with the situation where a usufructuary does share in the insurance: in that case, the usufructuary continues to benefit from a new building if one is constructed, or receives interest on the indemnity. Here, though, should the usufructuary have refused to contribute to the insurance, the owner insuring the tenement alone, the article says the owner shall receive the full amount of the insurance indemnity in case of loss. The usufructuary's refusal to share the cost is what shifts the full benefit of that insurance to the owner alone.
Why this makes sense as a matter of fairness
Insurance indemnity generally reflects the value of what was insured, paid for by whoever bore the cost of the premiums. Where the usufructuary declined to contribute anything toward that cost, letting the owner alone carry the expense of insuring the property, it follows that the owner alone should also receive the full benefit if the insured event occurs. The usufructuary cannot decline to share in the cost and then expect to share equally in the payout that the owner's own premiums secured.
The right the usufructuary still keeps
Article 608 does not leave the usufructuary with nothing at all; it closes with saving always the right granted to the usufructuary in the preceding article. This means whatever right the usufructuary was given under that other provision continues to apply, even where the usufructuary refused to contribute to the insurance and the owner receives the full indemnity here. The refusal to share in insurance costs does not strip the usufructuary of every protection available under the broader rules governing usufruct.
What this means practically
If you are a usufructuary who declined to help pay for insurance the owner arranged on the tenement, Article 608 means you should not expect a share of the insurance payout if the property is lost, since that benefit goes fully to the owner in this situation. Whatever separate right you may still hold under the related provision the article preserves is a distinct question from the insurance indemnity itself, and does not depend on having contributed to the insurance premium in the first place.