I don't know about the claim that the Jews might supply French rather than English cloth to the Turks. The English merchants fancifully suggest that the Jews might actually replace the French as competitors of the English. They are at pains to say that being of a different religion should not be a bar to doing business, but this is hardly surprising if they are planning to trade with Muslim Turks through the agency of Sephardic Jews and Armenian Christians.
The JEWS now desired to be admitted into a share of the trade, and the demand of the generality of the people was for an open commerce, or a limitation of the charter granted to the TURKEY company: the JEWS were strongly objected to, particularly by those members of the company who had most experience in the trade. The consideration of difference in religion among people subject to one common government, does not seem essential in commercial affairs, nor is it regarded much in our EUROPEAN trade; but the great influence they are supposed to have in ASIA, created an insuperable difficulty to their admittance. It seemed natural to believe, that by admitting no other JEWS than those of LONDON, and placing these under the fame common restrictions as other subjects, .that they would employ their power in favour of this nation, under whose government they are happy. It appeared however on this occasion, as if they were doomed to be excluded on account of their religion, at least it seemed a hard supposition, that EUROPEAN JEWS mould be at the bottom of all schemes against EUROPEAN trade with ASIA, as was then alledged. It was further objected, that the JEWS in CONSTANTINOPLE would promote a monopoly of the TURKEY commodities with the JEWS in ENGLAND, to the prejudice of the other subjects of this nation, and that the JEWISH factors abroad would underwork the CHRISTIANS: it was also urged, that the influence of the JEWS, arising from their great riches, would have too great a weight in the commercial scale. But was not this an acknowledgment that they were bold traders, possessed of large capitals, and would be contented with small profits? if it was, and that the trade was really in danger of being loft to this nation, were not these the very people who bid fairest to rival the FRENCH? There was yet a further objection, that they might go to market to MARSEILLES for their cloths, and only bring their silk here: even this might be preferable to the loss of the trade, for all commodities which we manufacture at home, are certainly great national benefits: but it was reasonable to imagine, that the JEWS under the protection of the BRITISH crown, might be restrained to a subjection to BRITISH laws, as well in commerce as in civil society in general.
It was however allowed, that the JEWS who reside in TURKEY are, for the most part, an immoral people, and have by a kind of confederacy established an exorbitant brokerage of i or more per cent. as it were by inheritance; and this reason, joined to others of the like nature, induced the FRENCH to stipulate with the TURKS, that they might not be obliged to employ JEWS. The debate, which at this time ran high, was at length reduced to this issue, viz. whether the liberty of trading to TURKEY should be granted to all his majesty's subjects, or to all his christian subjects only; and whether it should be made an open trade, or continue exclusive under the restrictions the legislature might judge necessary. Upon this occasion the following bill for enlarging and regulating the trade to the LEVANT seas was proposed to the parliament.
Source: Jonas Hanway. An historical account of the British trade over the Caspian sea. 1753.